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Garcia Delgado L, Derome A, Longpré S, Giroux-Dansereau M, Basbous G, Lavoie C, Saucier C, Denault JB. Spatiotemporal regulation of the hepatocyte growth factor receptor MET activity by sorting nexins 1/2 in HCT116 colorectal cancer cells. Biosci Rep 2024; 44:BSR20240182. [PMID: 38836326 PMCID: PMC11196213 DOI: 10.1042/bsr20240182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 05/31/2024] [Accepted: 06/04/2024] [Indexed: 06/06/2024] Open
Abstract
Cumulative research findings support the idea that endocytic trafficking is crucial in regulating receptor signaling and associated diseases. Specifically, strong evidence points to the involvement of sorting nexins (SNXs), particularly SNX1 and SNX2, in the signaling and trafficking of the receptor tyrosine kinase (RTK) MET in colorectal cancer (CRC). Activation of hepatocyte growth factor (HGF) receptor MET is a key driver of CRC progression. In the present study, we utilized human HCT116 CRC cells with SNX1 and SNX2 genes knocked out to demonstrate that their absence leads to a delay in MET entering early endosomes. This delay results in increased phosphorylation of both MET and AKT upon HGF stimulation, while ERK1/2 (extracellular signal-regulated kinases 1 and 2) phosphorylation remains unaffected. Despite these changes, HGF-induced cell proliferation, scattering, and migration remain similar between the parental and the SNX1/2 knockout cells. However, in the absence of SNX1 and SNX2, these cells exhibit increased resistance to TRAIL-induced apoptosis. This research underscores the intricate relationship between intracellular trafficking, receptor signaling, and cellular responses and demonstrates for the first time that the modulation of MET trafficking by SNX1 and SNX2 is critical for receptor signaling that may exacerbate the disease.
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Affiliation(s)
- Laiyen Garcia Delgado
- Department of Pharmacology and Physiology
- Pharmacology Institute of Sherbrooke (IPS)
- Université de Sherbrooke’s Cancer Research Institute (IRCUS), Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Amélie Derome
- Department of Pharmacology and Physiology
- Pharmacology Institute of Sherbrooke (IPS)
- Université de Sherbrooke’s Cancer Research Institute (IRCUS), Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
| | - Samantha Longpré
- Department of Pharmacology and Physiology
- Pharmacology Institute of Sherbrooke (IPS)
| | | | - Ghenwa Basbous
- Université de Sherbrooke’s Cancer Research Institute (IRCUS), Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences
| | - Christine Lavoie
- Department of Pharmacology and Physiology
- Pharmacology Institute of Sherbrooke (IPS)
- Université de Sherbrooke’s Cancer Research Institute (IRCUS), Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Centre de Recherche Clinique CHUS
| | - Caroline Saucier
- Université de Sherbrooke’s Cancer Research Institute (IRCUS), Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences
- Centre de Recherche Clinique CHUS
| | - Jean-Bernard Denault
- Department of Pharmacology and Physiology
- Pharmacology Institute of Sherbrooke (IPS)
- Université de Sherbrooke’s Cancer Research Institute (IRCUS), Université de Sherbrooke, 3001 12e Avenue Nord, Sherbrooke, QC J1H 5N4, Canada
- Department of Immunology and Cell Biology, Faculty of Medicine and Health Sciences
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Shi P, Tian Y, Xu F, Liu LN, Wu WH, Shi YZ, Dai AQ, Fang HY, Li KX, Xu C. Assessment of pathogenicity and functional characterization of APPL1 gene mutations in diabetic patients. World J Diabetes 2024; 15:275-286. [PMID: 38464380 PMCID: PMC10921161 DOI: 10.4239/wjd.v15.i2.275] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/02/2023] [Revised: 11/22/2023] [Accepted: 01/09/2024] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND Adaptor protein, phosphotyrosine interacting with PH domain and leucine zipper 1 (APPL1) plays a crucial role in regulating insulin signaling and glucose metabolism. Mutations in the APPL1 gene have been associated with the development of maturity-onset diabetes of the young type 14 (MODY14). Currently, only two mutations [c.1655T>A (p.Leu552*) and c.281G>A p.(Asp94Asn)] have been identified in association with this disease. Given the limited understanding of MODY14, it is imperative to identify additional cases and carry out comprehensive research on MODY14 and APPL1 mutations. AIM To assess the pathogenicity of APPL1 gene mutations in diabetic patients and to characterize the functional role of the APPL1 domain. METHODS Patients exhibiting clinical signs and a medical history suggestive of MODY were screened for the study. Whole exome sequencing was performed on the patients as well as their family members. The pathogenicity of the identified APPL1 variants was predicted on the basis of bioinformatics analysis. In addition, the pathogenicity of the novel APPL1 variant was preliminarily evaluated through in vitro functional experiments. Finally, the impact of these variants on APPL1 protein expression and the insulin pathway were assessed, and the potential mechanism underlying the interaction between the APPL1 protein and the insulin receptor was further explored. RESULTS A total of five novel mutations were identified, including four missense mutations (Asp632Tyr, Arg633His, Arg532Gln, and Ile642Met) and one intronic mutation (1153-16A>T). Pathogenicity prediction analysis revealed that the Arg532Gln was pathogenic across all predictions. The Asp632Tyr and Arg633His variants also had pathogenicity based on MutationTaster. In addition, multiple alignment of amino acid sequences showed that the Arg532Gln, Asp632Tyr, and Arg633His variants were conserved across different species. Moreover, in in vitro functional experiments, both the c.1894G>T (at Asp632Tyr) and c.1595G>A (at Arg532Gln) mutations were found to downregulate the expression of APPL1 on both protein and mRNA levels, indicating their pathogenic nature. Therefore, based on the patient's clinical and family history, combined with the results from bioinformatics analysis and functional experiment, the c.1894G>T (at Asp632Tyr) and c.1595G>A (at Arg532Gln) mutations were classified as pathogenic mutations. Importantly, all these mutations were located within the phosphotyrosine-binding domain of APPL1, which plays a critical role in the insulin sensitization effect. CONCLUSION This study provided new insights into the pathogenicity of APPL1 gene mutations in diabetes and revealed a potential target for the diagnosis and treatment of the disease.
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Affiliation(s)
- Ping Shi
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - Yang Tian
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - Feng Xu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - Lu-Na Liu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - Wan-Hong Wu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - Ying-Zhou Shi
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - An-Qi Dai
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - Hang-Yu Fang
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
| | - Kun-Xia Li
- Department of Pediatric, Yantai Yuhuangding Hospital Affiliated to Qingdao University, Yantai 264099, Shandong Province, China
| | - Chao Xu
- Department of Endocrinology, Shandong Provincial Hospital Affiliated to Shandong First Medical University, Jinan 250021, Shandong Province, China
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Tu X, Zhang H, Chen S, Ding YH, Wu X, Liang R, Shi SS. LncRNA CEBPA-AS1 alleviates cerebral ischemia-reperfusion injury by sponging miR-340-5p regulating APPL1/LKB1/AMPK pathway. FASEB J 2021; 36:e22075. [PMID: 34919285 DOI: 10.1096/fj.202100826rr] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2021] [Revised: 11/03/2021] [Accepted: 11/15/2021] [Indexed: 11/11/2022]
Abstract
Long non-coding RNAs (lncRNAs) regulate neurological damage in cerebral ischemia-reperfusion injury (CIRI). This study aimed to investigate the biological roles of lncRNA CEBPA-AS1 in CIRI. Middle cerebral artery occlusion and ischemia-reperfusion injury (MCAO/IR) rat model and oxygen-glucose deprivation and reoxygenation (OGD/R) cell lines were generated; the expression of CEBPA-AS1 was evaluated by qRT-PCR. The effects of CEBPA-AS1 on cell apoptosis and nerve damage were examined. The downstream microRNA (miRNA) and mRNA of CEBPA-AS1 were predicted and verified. We found that overexpression of CEBPA-AS1 could attenuate MCAO/IR-induced nerve damage and neuronal apoptosis in the rat model. Knockdown of CEBPA-AS1 aggravated cell apoptosis and enhanced the production of LDH and MDA in the OGD/R cells. Upon examining the molecular mechanisms, we found that CEBPA-AS1 stimulated APPL1 expression by combining with miR-340-5p, thereby regulating the APPL1/LKB1/AMPK pathway. In the rescue experiments, CEBPA-AS1 overexpression was found to attenuate OGD/R-induced cell apoptosis and MCAO/IR induced nerve damage, while miR-340-5p reversed these effects of CEBPA-AS1. In conclusion, CEBPA-AS1 could decrease CIRI by sponging miR-340-5, regulating the APPL1/LKB1/AMPK pathway.
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Affiliation(s)
- Xiankun Tu
- Department of Neurosurgery, Neurosurgical Institute of Fujian Province, Fujian Medical University Union Hospital, Fuzhou, China
| | - Huabin Zhang
- Department of Neurosurgery, Neurosurgical Institute of Fujian Province, Fujian Medical University Union Hospital, Fuzhou, China
| | - Song Chen
- Department of Neurosurgery, Neurosurgical Institute of Fujian Province, Fujian Medical University Union Hospital, Fuzhou, China
| | - Yi-Hang Ding
- Department of Neurosurgery, Neurosurgical Institute of Fujian Province, Fujian Medical University Union Hospital, Fuzhou, China
| | - Xiyao Wu
- Department of Neurosurgery, Neurosurgical Institute of Fujian Province, Fujian Medical University Union Hospital, Fuzhou, China
| | - Risheng Liang
- Department of Neurosurgery, Neurosurgical Institute of Fujian Province, Fujian Medical University Union Hospital, Fuzhou, China
| | - Song-Sheng Shi
- Department of Neurosurgery, Neurosurgical Institute of Fujian Province, Fujian Medical University Union Hospital, Fuzhou, China
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Padarti A, Abou-Fadel J, Zhang J. Resurgence of phosphotyrosine binding domains: Structural and functional properties essential for understanding disease pathogenesis. Biochim Biophys Acta Gen Subj 2021; 1865:129977. [PMID: 34391832 DOI: 10.1016/j.bbagen.2021.129977] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 07/30/2021] [Accepted: 07/30/2021] [Indexed: 11/28/2022]
Abstract
BACKGROUND Phosphotyrosine Binding (PTB) Domains, usually found on scaffold proteins, are pervasive in many cellular signaling pathways. These domains are the second-largest family of phosphotyrosine recognition domains and since their initial discovery, dozens of PTB domains have been structurally determined. SCOPE OF REVIEW Due to its signature sequence flexibility, PTB domains can bind to a large variety of ligands including phospholipids. PTB peptide binding is divided into classical binding (canonical NPXY motifs) and non-classical binding (all other motifs). The first atypical PTB domain was discovered in cerebral cavernous malformation 2 (CCM2) protein, while only one third in size of the typical PTB domain, it remains functionally equivalent. MAJOR CONCLUSIONS PTB domains are involved in numerous signaling processes including embryogenesis, neurogenesis, and angiogenesis, while dysfunction is linked to major disorders including diabetes, hypercholesterolemia, Alzheimer's disease, and strokes. PTB domains may also be essential in infectious processes, currently responsible for the global pandemic in which viral cellular entry is suspected to be mediated through PTB and NPXY interactions. GENERAL SIGNIFICANCE We summarize the structural and functional updates in the PTB domain over the last 20 years in hopes of resurging interest and further analyzing the importance of this versatile domain.
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Affiliation(s)
- Akhil Padarti
- Department of Molecular and Translational Medicine (MTM), Texas Tech University Health Science Center El Paso, 5001 El Paso Drive, El Paso, TX 79905, USA
| | - Johnathan Abou-Fadel
- Department of Molecular and Translational Medicine (MTM), Texas Tech University Health Science Center El Paso, 5001 El Paso Drive, El Paso, TX 79905, USA
| | - Jun Zhang
- Department of Molecular and Translational Medicine (MTM), Texas Tech University Health Science Center El Paso, 5001 El Paso Drive, El Paso, TX 79905, USA.
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Sanchez Caballero L, Gorgogietas V, Arroyo MN, Igoillo-Esteve M. Molecular mechanisms of β-cell dysfunction and death in monogenic forms of diabetes. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 359:139-256. [PMID: 33832649 DOI: 10.1016/bs.ircmb.2021.02.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Monogenetic forms of diabetes represent 1%-5% of all diabetes cases and are caused by mutations in a single gene. These mutations, that affect genes involved in pancreatic β-cell development, function and survival, or insulin regulation, may be dominant or recessive, inherited or de novo. Most patients with monogenic diabetes are very commonly misdiagnosed as having type 1 or type 2 diabetes. The severity of their symptoms depends on the nature of the mutation, the function of the affected gene and, in some cases, the influence of additional genetic or environmental factors that modulate severity and penetrance. In some patients, diabetes is accompanied by other syndromic features such as deafness, blindness, microcephaly, liver and intestinal defects, among others. The age of diabetes onset may also vary from neonatal until early adulthood manifestations. Since the different mutations result in diverse clinical presentations, patients usually need different treatments that range from just diet and exercise, to the requirement of exogenous insulin or other hypoglycemic drugs, e.g., sulfonylureas or glucagon-like peptide 1 analogs to control their glycemia. As a consequence, awareness and correct diagnosis are crucial for the proper management and treatment of monogenic diabetes patients. In this chapter, we describe mutations causing different monogenic forms of diabetes associated with inadequate pancreas development or impaired β-cell function and survival, and discuss the molecular mechanisms involved in β-cell demise.
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Affiliation(s)
- Laura Sanchez Caballero
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Vyron Gorgogietas
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Maria Nicol Arroyo
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/
| | - Mariana Igoillo-Esteve
- ULB Center for Diabetes Research (UCDR), Université Libre de Bruxelles, Brussels, Belgium. http://www.ucdr.be/.
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York HM, Patil A, Moorthi UK, Kaur A, Bhowmik A, Hyde GJ, Gandhi H, Fulcher A, Gaus K, Arumugam S. Rapid whole cell imaging reveals a calcium-APPL1-dynein nexus that regulates cohort trafficking of stimulated EGF receptors. Commun Biol 2021; 4:224. [PMID: 33597720 PMCID: PMC7889693 DOI: 10.1038/s42003-021-01740-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 01/22/2021] [Indexed: 01/31/2023] Open
Abstract
The endosomal system provides rich signal processing capabilities for responses elicited by growth factor receptors and their ligands. At the single cell level, endosomal trafficking becomes a critical component of signal processing, as exemplified by the epidermal growth factor (EGF) receptors. Activated EGFRs are trafficked to the phosphatase-enriched peri-nuclear region (PNR), where they are dephosphorylated and degraded. The details of the mechanisms that govern the movements of stimulated EGFRs towards the PNR, are not completely known. Here, exploiting the advantages of lattice light-sheet microscopy, we show that EGFR activation by EGF triggers a transient calcium increase causing a whole-cell level redistribution of Adaptor Protein, Phosphotyrosine Interacting with PH Domain And Leucine Zipper 1 (APPL1) from pre-existing endosomes within one minute, the rebinding of liberated APPL1 directly to EGFR, and the dynein-dependent translocation of APPL1-EGF-bearing endosomes to the PNR within ten minutes. The cell spanning, fast acting network that we reveal integrates a cascade of events dedicated to the cohort movement of activated EGF receptors. Our findings support the intriguing proposal that certain endosomal pathways have shed some of the stochastic strategies of traditional trafficking and have evolved processes that provide the temporal predictability that typify canonical signaling.
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Affiliation(s)
- H. M. York
- grid.1002.30000 0004 1936 7857Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC Australia ,grid.1002.30000 0004 1936 7857European Molecular Biological Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, VIC Australia
| | - A. Patil
- grid.1002.30000 0004 1936 7857Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC Australia ,grid.1002.30000 0004 1936 7857European Molecular Biological Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, VIC Australia
| | - U. K. Moorthi
- grid.1002.30000 0004 1936 7857Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC Australia ,grid.1002.30000 0004 1936 7857European Molecular Biological Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, VIC Australia
| | - A. Kaur
- grid.1005.40000 0004 4902 0432Single Molecule Science, University of New South Wales, Sydney, Australia
| | - A. Bhowmik
- grid.1005.40000 0004 4902 0432Single Molecule Science, University of New South Wales, Sydney, Australia
| | | | - H. Gandhi
- grid.1002.30000 0004 1936 7857Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC Australia ,grid.1002.30000 0004 1936 7857European Molecular Biological Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, VIC Australia
| | - A. Fulcher
- grid.1002.30000 0004 1936 7857Monash Micro Imaging, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC Australia
| | - K. Gaus
- grid.1005.40000 0004 4902 0432Single Molecule Science, University of New South Wales, Sydney, Australia ,grid.1005.40000 0004 4902 0432ARC Centre of Excellence in Advanced Molecular Imaging, UNSW, Sydney, Australia
| | - S. Arumugam
- grid.1002.30000 0004 1936 7857Monash Biomedicine Discovery Institute, Faculty of Medicine, Nursing and Health Sciences, Monash University, Clayton/Melbourne, VIC Australia ,grid.1002.30000 0004 1936 7857European Molecular Biological Laboratory Australia (EMBL Australia), Monash University, Clayton/Melbourne, VIC Australia ,grid.1005.40000 0004 4902 0432Single Molecule Science, University of New South Wales, Sydney, Australia ,grid.1005.40000 0004 4902 0432ARC Centre of Excellence in Advanced Molecular Imaging, UNSW, Sydney, Australia
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Chen Y, Zhang W, Chen B, Liu Y, Dong Y, Xu A, Hao Q. Crystal Structure of Human APPL BAR-PH Heterodimer Reveals a Flexible Dimeric BAR curve: Implication in Mutual Regulation of Endosomal Targeting. Biochem J 2020; 477:BCJ20200438. [PMID: 33258922 DOI: 10.1042/bcj20200438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2020] [Revised: 11/24/2020] [Accepted: 11/30/2020] [Indexed: 11/17/2022]
Abstract
The APPL (adaptor proteins containing pleckstrin homology domain, phosphotyrosine binding domain and a leucine zipper motif) family consists of two isoforms, APPL1 and APPL2. By binding to curved plasma membrane, these adaptor proteins associate with multiple transmembrane receptors and recruit various downstream signaling components. They are involved in the regulation of signaling pathways evoked by a variety of extracellular stimuli, such as adiponectin, insulin, FSH (follicle stimulating hormone), EGF (epidermal growth factor). And they play important roles in cell proliferation, apoptosis, glucose uptake, insulin secretion and sensitivity. However, emerging evidence suggests that APPL1 and APPL2 perform different or even opposite functions and the underlying mechanism remains unclear. As APPL proteins can either homodimerize or heterodimerize in vivo, we hypothesized that heterodimerization of APPL proteins might account for the mechanism. By solving the crystal structure of APPL1-APPL2 BAR-PH heterodimer, we find that the overall structure is crescent-shaped with a longer curvature radius of 76 Å, compared to 55 Å of the APPL1 BAR-PH homodimer. However, there is no significant difference of the curvature between APPL BAR-PH heterodimer and APPL2 homodimer. The data suggest that the APPL1 BAR-PH homodimer, APPL2 BAR-PH homodimer and APPL1/APPL2 BAR-PH heterodimer may bind to endosomes of different sizes. Different positive charge distribution is observed on the concave surface of APPL BAR-PH heterodimer than the homodimers, which may change the affinity of membrane association and subcellular localization. Collectively, APPL2 may regulate APPL1 function through altering the preference of endosome binding by heterodimerization.
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Affiliation(s)
- Yujie Chen
- University of Hong Kong, Hong Kong, China
| | - Wen Zhang
- University of Hong Kong, Hong Kong, China
| | - Bin Chen
- University of Hong Kong, Hong Kong, China
| | - Ying Liu
- Institute of High Energy Physics, CAS, Beijing, China
| | - Yuhui Dong
- Institute of High Energy Physics, CAS, Beijing, China
| | - Aimin Xu
- University of Hong Kong, Hong Kong, China
| | - Quan Hao
- University of Hong Kong, Hong Kong, China
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Nader N, Dib M, Hodeify R, Courjaret R, Elmi A, Hammad AS, Dey R, Huang XY, Machaca K. Membrane progesterone receptor induces meiosis in Xenopus oocytes through endocytosis into signaling endosomes and interaction with APPL1 and Akt2. PLoS Biol 2020; 18:e3000901. [PMID: 33137110 PMCID: PMC7660923 DOI: 10.1371/journal.pbio.3000901] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 11/12/2020] [Accepted: 09/18/2020] [Indexed: 12/13/2022] Open
Abstract
The steroid hormone progesterone (P4) mediates many physiological processes through either nuclear receptors that modulate gene expression or membrane P4 receptors (mPRs) that mediate nongenomic signaling. mPR signaling remains poorly understood. Here we show that the topology of mPRβ is similar to adiponectin receptors and opposite to that of G-protein-coupled receptors (GPCRs). Using Xenopus oocyte meiosis as a well-established physiological readout of nongenomic P4 signaling, we demonstrate that mPRβ signaling requires the adaptor protein APPL1 and the kinase Akt2. We further show that P4 induces clathrin-dependent endocytosis of mPRβ into signaling endosome, where mPR interacts transiently with APPL1 and Akt2 to induce meiosis. Our findings outline the early steps involved in mPR signaling and expand the spectrum of mPR signaling through the multitude of pathways involving APPL1. The steroid hormone progesterone mediates many physiological processes through either nuclear receptors that modulate gene expression, or membrane progesterone receptors (mPRs) that mediate non-genomic signaling. This study shows that non-genomic mPRβ signaling progresses through clathrin-dependent endocytosis into signaling endosomes where it interacts with and activates APPL1 and Akt2 to induce oocyte meiosis.
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Affiliation(s)
- Nancy Nader
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
- Calcium Signaling Group, Weill Cornell Medicine Qatar
| | - Maya Dib
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
- Calcium Signaling Group, Weill Cornell Medicine Qatar
| | - Rawad Hodeify
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
- Calcium Signaling Group, Weill Cornell Medicine Qatar
| | - Raphael Courjaret
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
- Calcium Signaling Group, Weill Cornell Medicine Qatar
| | - Asha Elmi
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
- Calcium Signaling Group, Weill Cornell Medicine Qatar
- College of Health and Life Science, Hamad bin Khalifa University, Doha, Qatar
| | - Ayat S. Hammad
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
- Calcium Signaling Group, Weill Cornell Medicine Qatar
- College of Health and Life Science, Hamad bin Khalifa University, Doha, Qatar
| | - Raja Dey
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, United States of America
| | - Xin-Yun Huang
- Department of Physiology and Biophysics, Weill Cornell Medicine, New York, United States of America
| | - Khaled Machaca
- Department of Physiology and Biophysics, Weill Cornell Medicine Qatar, Education City, Qatar Foundation, Doha, Qatar
- Calcium Signaling Group, Weill Cornell Medicine Qatar
- * E-mail:
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Molecular Regulation of the RhoGAP GRAF3 and Its Capacity to Limit Blood Pressure In Vivo. Cells 2020; 9:cells9041042. [PMID: 32331391 PMCID: PMC7226614 DOI: 10.3390/cells9041042] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Accepted: 04/20/2020] [Indexed: 12/26/2022] Open
Abstract
Anti-hypertensive therapies are usually prescribed empirically and are often ineffective. Given the prevalence and deleterious outcomes of hypertension (HTN), improved strategies are needed. We reported that the Rho-GAP GRAF3 is selectively expressed in smooth muscle cells (SMC) and controls blood pressure (BP) by limiting the RhoA-dependent contractility of resistance arterioles. Importantly, genetic variants at the GRAF3 locus controls BP in patients. The goal of this study was to validate GRAF3 as a druggable candidate for future anti-HTN therapies. Importantly, using a novel mouse model, we found that modest induction of GRAF3 in SMC significantly decreased basal and vasoconstrictor-induced BP. Moreover, we found that GRAF3 protein toggles between inactive and active states by processes controlled by the mechano-sensing kinase, focal adhesion kinase (FAK). Using resonance energy transfer methods, we showed that agonist-induced FAK-dependent phosphorylation at Y376GRAF3 reverses an auto-inhibitory interaction between the GAP and BAR-PH domains. Y376 is located in a linker between the PH and GAP domains and is invariant in GRAF3 homologues and a phosphomimetic E376GRAF3 variant exhibited elevated GAP activity. Collectively, these data provide strong support for the future identification of allosteric activators of GRAF3 for targeted anti-hypertensive therapies.
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Fan L, Ye H, Wan Y, Qin L, Zhu L, Su J, Zhu X, Zhang L, Miao Q, Zhang Q, Zhang Z, Xu A, Li Y, Li X, Wang Y. Adaptor protein APPL1 coordinates HDAC3 to modulate brown adipose tissue thermogenesis in mice. Metabolism 2019; 100:153955. [PMID: 31390528 DOI: 10.1016/j.metabol.2019.153955] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Revised: 07/12/2019] [Accepted: 07/31/2019] [Indexed: 01/17/2023]
Abstract
OBJECTIVES The activation of brown adipose tissue (BAT) is considered as a promising therapeutic target for obesity. APPL1 (Adaptor protein containing the Pleckstrin homology domain, Phosphotyrosine binding domain and Leucine zipper motif) is an intracellular adaptor protein and its genetic variation is correlated with BMI and body fat distribution in diabetic patients. However, little is known about the roles of APPL1 in BAT thermogenesis. MATERIALS/METHODS In this study, adipose tissue specific knockout (ASKO) mice were generated to evaluate APPL1's role in BAT thermogenesis in vivo, and possible signaling pathways were further explored in cultured brown adipocytes. RESULTS After high fat diet challenge, APPL1 ASKO mice developed more severe obesity, glucose intolerance and insulin resistance compared with control mice. Metabolic cage study showed that APPL1 deficiency impaired energy expenditure and adaptive thermogenesis in ASKO mice. PET-CT analysis showed decreased standardized uptake value (SUV) in the inter-scapular region which indicated impaired BAT activity in ASKO mice. Further study showed deletion of APPL1 attenuated brown fat specific gene expression, such as UCP1 and PGC1α in both BAT and brown adipocytes. In cultured brown adipocytes, upon cAMP stimulation, APPL1 shuttled from cytosol to nuclei. Co-IP and ChIP study showed that APPL1 could directly interact with histone deacetylase 3 (HDAC3) to mediate chromatin remodeling and UCP1 gene expression. CONCLUSIONS Our data demonstrated the essential role of APPL1 in regulating brown adipocytes thermogenesis via interaction with HDAC3, which may have potential therapeutic implications for treatment of obesity.
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Affiliation(s)
- Linling Fan
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Hongying Ye
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Yun Wan
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Lang Qin
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Lu Zhu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Jing Su
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Xiaoming Zhu
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Lv Zhang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Qing Miao
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Qiongyue Zhang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Zhaoyun Zhang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Aimin Xu
- Department of Medicine, the University of Hong Kong, Hong Kong
| | - Yiming Li
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China
| | - Xi Li
- Institute of Life Sciences, Chongqing Medical University, China.
| | - Yi Wang
- Department of Endocrinology and Metabolism, Huashan Hospital, Fudan University, Shanghai, China.
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11
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Chan C, Pang X, Zhang Y, Niu T, Yang S, Zhao D, Li J, Lu L, Hsu VW, Zhou J, Sun F, Fan J. ACAP1 assembles into an unusual protein lattice for membrane deformation through multiple stages. PLoS Comput Biol 2019; 15:e1007081. [PMID: 31291238 PMCID: PMC6663034 DOI: 10.1371/journal.pcbi.1007081] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Revised: 07/29/2019] [Accepted: 05/06/2019] [Indexed: 11/19/2022] Open
Abstract
Studies on the Bin-Amphiphysin-Rvs (BAR) domain have advanced a fundamental understanding of how proteins deform membrane. We previously showed that a BAR domain in tandem with a Pleckstrin Homology (PH domain) underlies the assembly of ACAP1 (Arfgap with Coil-coil, Ankryin repeat, and PH domain I) into an unusual lattice structure that also uncovers a new paradigm for how a BAR protein deforms membrane. Here, we initially pursued computation-based refinement of the ACAP1 lattice to identify its critical protein contacts. Simulation studies then revealed how ACAP1, which dimerizes into a symmetrical structure in solution, is recruited asymmetrically to the membrane through dynamic behavior. We also pursued electron microscopy (EM)-based structural studies, which shed further insight into the dynamic nature of the ACAP1 lattice assembly. As ACAP1 is an unconventional BAR protein, our findings broaden the understanding of the mechanistic spectrum by which proteins assemble into higher-ordered structures to achieve membrane deformation.
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Affiliation(s)
- Chun Chan
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
| | - Xiaoyun Pang
- National Laboratory of Biomacromolecules, CAS Center for excellence in biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Yan Zhang
- National Laboratory of Biomacromolecules, CAS Center for excellence in biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Tongxin Niu
- National Laboratory of Biomacromolecules, CAS Center for excellence in biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
| | - Shengjiang Yang
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong, China
| | - Daohui Zhao
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong, China
| | - Jian Li
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, and Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Lanyuan Lu
- School of Biological Sciences, Nanyang Technological University, Singapore
| | - Victor W. Hsu
- Division of Rheumatology, Immunology and Allergy, Brigham and Women’s Hospital, and Department of Medicine, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jian Zhou
- School of Chemistry and Chemical Engineering, South China University of Technology, Guangzhou, Guangdong, China
- * E-mail: (JZ); (FS); (JF)
| | - Fei Sun
- National Laboratory of Biomacromolecules, CAS Center for excellence in biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing, China
- * E-mail: (JZ); (FS); (JF)
| | - Jun Fan
- Department of Materials Science and Engineering, City University of Hong Kong, Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
- Center for Advanced Nuclear Safety and Sustainable Development, City University of Hong Kong, Hong Kong, China
- * E-mail: (JZ); (FS); (JF)
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12
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Pemberton JG, Balla T. Polyphosphoinositide-Binding Domains: Insights from Peripheral Membrane and Lipid-Transfer Proteins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1111:77-137. [PMID: 30483964 DOI: 10.1007/5584_2018_288] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Within eukaryotic cells, biochemical reactions need to be organized on the surface of membrane compartments that use distinct lipid constituents to dynamically modulate the functions of integral proteins or influence the selective recruitment of peripheral membrane effectors. As a result of these complex interactions, a variety of human pathologies can be traced back to improper communication between proteins and membrane surfaces; either due to mutations that directly alter protein structure or as a result of changes in membrane lipid composition. Among the known structural lipids found in cellular membranes, phosphatidylinositol (PtdIns) is unique in that it also serves as the membrane-anchored precursor of low-abundance regulatory lipids, the polyphosphoinositides (PPIn), which have restricted distributions within specific subcellular compartments. The ability of PPIn lipids to function as signaling platforms relies on both non-specific electrostatic interactions and the selective stereospecific recognition of PPIn headgroups by specialized protein folds. In this chapter, we will attempt to summarize the structural diversity of modular PPIn-interacting domains that facilitate the reversible recruitment and conformational regulation of peripheral membrane proteins. Outside of protein folds capable of capturing PPIn headgroups at the membrane interface, recent studies detailing the selective binding and bilayer extraction of PPIn species by unique functional domains within specific families of lipid-transfer proteins will also be highlighted. Overall, this overview will help to outline the fundamental physiochemical mechanisms that facilitate localized interactions between PPIn lipids and the wide-variety of PPIn-binding proteins that are essential for the coordinate regulation of cellular metabolism and membrane dynamics.
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Affiliation(s)
- Joshua G Pemberton
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
| | - Tamas Balla
- Section on Molecular Signal Transduction, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
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13
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Diggins NL, Kang H, Weaver A, Webb DJ. α5β1 integrin trafficking and Rac activation are regulated by APPL1 in a Rab5-dependent manner to inhibit cell migration. J Cell Sci 2018; 131:jcs.207019. [PMID: 29361527 DOI: 10.1242/jcs.207019] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Accepted: 01/09/2018] [Indexed: 01/04/2023] Open
Abstract
Cell migration is a tightly coordinated process that requires the spatiotemporal regulation of many molecular components. Because adaptor proteins can serve as integrators of cellular events, they are being increasingly studied as regulators of cell migration. The adaptor protein containing a pleckstrin-homology (PH) domain, phosphotyrosine binding (PTB) domain, and leucine zipper motif 1 (APPL1) is a 709 amino acid endosomal protein that plays a role in cell proliferation and survival as well as endosomal trafficking and signaling. However, its function in regulating cell migration is poorly understood. Here, we show that APPL1 hinders cell migration by modulating both trafficking and signaling events controlled by Rab5 in cancer cells. APPL1 decreases internalization and increases recycling of α5β1 integrin, leading to higher levels of α5β1 integrin at the cell surface that hinder adhesion dynamics. Furthermore, APPL1 decreases the activity of the GTPase Rac and its effector PAK, which in turn regulate cell migration. Thus, we demonstrate a novel role for the interaction between APPL1 and Rab5 in governing crosstalk between signaling and trafficking pathways on endosomes to affect cancer cell migration.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Nicole L Diggins
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA
| | - Hakmook Kang
- Department of Biostatistics, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Alissa Weaver
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Donna J Webb
- Department of Biological Sciences, Vanderbilt University, Nashville, TN 37232, USA.,Department of Cancer Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.,Vanderbilt Kennedy Center, Vanderbilt University Medical Center, Nashville, TN 37232, USA
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14
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Galan-Davila AK, Ryu J, Dong K, Xiao Y, Dai Z, Zhang D, Li Z, Dick AM, Liu KD, Kamat A, Lu M, Dong Q, Liu F, Dong LQ. Alternative splicing variant of the scaffold protein APPL1 suppresses hepatic adiponectin signaling and function. J Biol Chem 2018; 293:6064-6074. [PMID: 29483192 DOI: 10.1074/jbc.ra118.002162] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/09/2018] [Indexed: 11/06/2022] Open
Abstract
Adiponectin is an adipocyte-derived hormone with antidiabetic activities that include increasing the sensitivity of cells to insulin. Adaptor protein containing pleckstrin homology domain, phosphotyrosine-binding domain, and leucine zipper motif (APPL1) stimulates adiponectin signaling and promotes adiponectin's insulin-sensitizing effects by binding to two adiponectin receptors, AdipoR1 and AdipoR2, and the insulin receptor. In this study, we report an alternative splicing variant of APPL1 (APPL1sv) that is highly expressed in mouse liver, pancreas, and spleen tissues. The expression levels of APPL1sv in liver tissues were enhanced in a mouse model of obesity and diabetic dyslipidemia (i.e. db/db mice) and reduced in calorie-restricted mice compared with ad libitum-fed mice. APPL1sv overexpression or suppression inhibited or enhanced, respectively, adiponectin-stimulated phosphorylation of AMP protein kinase (AMPK) in mouse hepatocytes. We also found that APPL1sv binds to AdipoR1 and AdipoR2 under basal conditions and that adiponectin treatment reduces this binding. Overexpression of APPL1sv blocked adiponectin-induced interactions of APPL1 with the adiponectin receptors. Moreover, adenovirus-mediated and short hairpin RNA-based suppression of APPL1sv greatly reduced high fat diet-induced insulin resistance and hepatic glucose production in mice. Our study identifies a key suppressor of hepatic adiponectin signaling and insulin sensitivity, a finding that may shed light on identifying effective therapeutic targets for treating insulin resistance and type 2 diabetes.
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Affiliation(s)
- Amanda K Galan-Davila
- From the Departments of Cell Systems and Anatomy.,the Department of Clinical and Applied Science Education, University of the Incarnate Word School of Osteopathic Medicine, San Antonio, Texas 78253
| | - Jiyoon Ryu
- From the Departments of Cell Systems and Anatomy
| | - Kun Dong
- From the Departments of Cell Systems and Anatomy
| | - Yang Xiao
- From the Departments of Cell Systems and Anatomy
| | - Zhe Dai
- From the Departments of Cell Systems and Anatomy
| | - Deling Zhang
- From the Departments of Cell Systems and Anatomy
| | - Zhi Li
- From the Departments of Cell Systems and Anatomy
| | | | - Kevin D Liu
- From the Departments of Cell Systems and Anatomy
| | - Amrita Kamat
- Medicine and.,The Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229-3900.,the Geriatric Research Education and Clinical Center (GRECC), South Texas Veterans Health Care System, San Antonio, Texas 78229
| | - Min Lu
- the Department of Medicine, University of California, San Diego, La Jolla, California 92093.,the Merck Research Laboratory, Diabetes Early Discovery, Boston, Massachusetts 02115-5727
| | - Qunfeng Dong
- the Center for Biomedical Informatics, Department of Public Health Sciences, Loyola University Chicago Stritch School of Medicine, Maywood, Illinois 60153, and
| | - Feng Liu
- The Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229-3900.,Pharmacology, and
| | - Lily Q Dong
- From the Departments of Cell Systems and Anatomy, .,The Barshop Center for Longevity and Aging Studies, University of Texas Health Science Center, San Antonio, Texas 78229-3900
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15
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Colacurcio DJ, Pensalfini A, Jiang Y, Nixon RA. Dysfunction of autophagy and endosomal-lysosomal pathways: Roles in pathogenesis of Down syndrome and Alzheimer's Disease. Free Radic Biol Med 2018; 114:40-51. [PMID: 28988799 PMCID: PMC5748263 DOI: 10.1016/j.freeradbiomed.2017.10.001] [Citation(s) in RCA: 118] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Revised: 10/03/2017] [Accepted: 10/04/2017] [Indexed: 12/12/2022]
Abstract
Individuals with Down syndrome (DS) have an increased risk of early-onset Alzheimer's Disease (AD), largely owing to a triplication of the APP gene, located on chromosome 21. In DS and AD, defects in endocytosis and lysosomal function appear at the earliest stages of disease development and progress to widespread failure of intraneuronal waste clearance, neuritic dystrophy and neuronal cell death. The same genetic factors that cause or increase AD risk are also direct causes of endosomal-lysosomal dysfunction, underscoring the essential partnership between this dysfunction and APP metabolites in AD pathogenesis. The appearance of APP-dependent endosome anomalies in DS beginning in infancy and evolving into the full range of AD-related endosomal-lysosomal deficits provides a unique opportunity to characterize the earliest pathobiology of AD preceding the classical neuropathological hallmarks. Facilitating this characterization is the authentic recapitulation of this endosomal pathobiology in peripheral cells from people with DS and in trisomy mouse models. Here, we review current research on endocytic-lysosomal dysfunction in DS and AD, the emerging importance of APP/βCTF in initiating this dysfunction, and the potential roles of additional trisomy 21 genes in accelerating endosomal-lysosomal impairment in DS. Collectively, these studies underscore the growing value of investigating DS to probe the biological origins of AD as well as to understand and ameliorate the developmental disability of DS.
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Affiliation(s)
- Daniel J Colacurcio
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
| | - Anna Pensalfini
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
| | - Ying Jiang
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA
| | - Ralph A Nixon
- Center for Dementia Research, Nathan S. Kline Institute, Orangeburg, NY 10962, USA; Department of Psychiatry, New York University Langone Medical Center, New York, NY 10016, USA; Department of Cell Biology, New York University Langone Medical Center, New York, NY 10016, USA.
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16
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APPL1 is a multifunctional endosomal signaling adaptor protein. Biochem Soc Trans 2017; 45:771-779. [PMID: 28620038 DOI: 10.1042/bst20160191] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 03/17/2017] [Accepted: 03/22/2017] [Indexed: 11/17/2022]
Abstract
Endosomal adaptor proteins are important regulators of signaling pathways underlying many biological processes. These adaptors can integrate signals from multiple pathways via localization to specific endosomal compartments, as well as through multiple protein-protein interactions. One such adaptor protein that has been implicated in regulating signaling pathways is the adaptor protein containing a pleckstrin homology (PH) domain, phosphotyrosine-binding (PTB) domain, and leucine zipper motif 1 (APPL1). APPL1 localizes to a subset of Rab5-positive endosomes through its Bin-Amphiphysin-Rvs and PH domains, and it coordinates signaling pathways through its interaction with many signaling receptors and proteins through its PTB domain. This review discusses our current understanding of the role of APPL1 in signaling and trafficking, as well as highlights recent work into the function of APPL1 in cell migration and adhesion.
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17
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Luo W, Janoštiak R, Tolde O, Ryzhova LM, Koudelková L, Dibus M, Brábek J, Hanks SK, Rosel D. ARHGAP42 is activated by Src-mediated tyrosine phosphorylation to promote cell motility. J Cell Sci 2017; 130:2382-2393. [PMID: 28584191 PMCID: PMC5536916 DOI: 10.1242/jcs.197434] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2016] [Accepted: 05/26/2017] [Indexed: 01/08/2023] Open
Abstract
The tyrosine kinase Src acts as a key regulator of cell motility by phosphorylating multiple protein substrates that control cytoskeletal and adhesion dynamics. In an earlier phosphotyrosine proteomics study, we identified a novel Rho-GTPase activating protein, now known as ARHGAP42, as a likely biologically relevant Src substrate. ARHGAP42 is a member of a family of RhoGAPs distinguished by tandem BAR-PH domains lying N-terminal to the GAP domain. Like other family members, ARHGAP42 acts preferentially as a GAP for RhoA. We show that Src principally phosphorylates ARHGAP42 on tyrosine 376 (Tyr-376) in the short linker between the BAR-PH and GAP domains. The expression of ARHGAP42 variants in mammalian cells was used to elucidate its regulation. We found that the BAR domain is inhibitory toward the GAP activity of ARHGAP42, such that BAR domain deletion resulted in decreased active GTP-bound RhoA and increased cell motility. With the BAR domain intact, ARHGAP42 GAP activity could be activated by phosphorylation of Tyr-376 to promote motile cell behavior. Thus, phosphorylation of ARHGAP42 Tyr-376 is revealed as a novel regulatory event by which Src can affect actin dynamics through RhoA inhibition.
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Affiliation(s)
- Weifeng Luo
- Department of Cell Biology, Charles University in Prague, Viničná 7, Prague, 12843, Czech Republic
| | - Radoslav Janoštiak
- Department of Cell Biology, Charles University in Prague, Viničná 7, Prague, 12843, Czech Republic
| | - Ondřej Tolde
- Department of Cell Biology, Charles University in Prague, Viničná 7, Prague, 12843, Czech Republic
- Department of Cell Biology, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University (BIOCEV), Průmyslová 595, Vestec u Prahy 25242, Czech Republic
| | - Larisa M Ryzhova
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Lenka Koudelková
- Department of Cell Biology, Charles University in Prague, Viničná 7, Prague, 12843, Czech Republic
- Department of Cell Biology, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University (BIOCEV), Průmyslová 595, Vestec u Prahy 25242, Czech Republic
| | - Michal Dibus
- Department of Cell Biology, Charles University in Prague, Viničná 7, Prague, 12843, Czech Republic
- Department of Cell Biology, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University (BIOCEV), Průmyslová 595, Vestec u Prahy 25242, Czech Republic
| | - Jan Brábek
- Department of Cell Biology, Charles University in Prague, Viničná 7, Prague, 12843, Czech Republic
- Department of Cell Biology, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University (BIOCEV), Průmyslová 595, Vestec u Prahy 25242, Czech Republic
| | - Steven K Hanks
- Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Daniel Rosel
- Department of Cell Biology, Charles University in Prague, Viničná 7, Prague, 12843, Czech Republic
- Department of Cell Biology, Biotechnology and Biomedicine Centre of the Academy of Sciences and Charles University (BIOCEV), Průmyslová 595, Vestec u Prahy 25242, Czech Republic
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18
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Zhang J, Dubey P, Padarti A, Zhang A, Patel R, Patel V, Cistola D, Badr A. Novel functions of CCM1 delimit the relationship of PTB/PH domains. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1274-1286. [PMID: 28698152 DOI: 10.1016/j.bbapap.2017.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 06/27/2017] [Accepted: 07/01/2017] [Indexed: 12/18/2022]
Abstract
BACKGROUND Three NPXY motifs and one FERM domain in CCM1 makes it a versatile scaffold protein for tethering the signaling components together within the CCM signaling complex (CSC). The cellular role of CCM1 protein remains inadequately expounded. Both phosphotyrosine binding (PTB) and pleckstrin homology (PH) domains were recognized as structurally related but functionally distinct domains. METHODS By utilizing molecular cloning, protein binding assays and RT-qPCR to identify novel cellular partners of CCM1 and its cellular expression patterns; by screening candidate PTB/PH proteins and subsequently structurally simulation in combining with current X-ray crystallography and NMR data to defined the essential structure of PTB/PH domain for NPXY-binding and the relationship among PTB, PH and FERM domain(s). RESULTS We identified a group of 28 novel cellular partners of CCM1, all of which contain either PTB or PH domain(s), and developed a novel classification system for these PTB/PH proteins based on their relationship with different NPXY motifs of CCM1. Our results demonstrated that CCM1 has a wide spectrum of binding to different PTB/PH proteins and perpetuates their specificity to interact with certain PTB/PH domains through selective combination of three NPXY motifs. We also demonstrated that CCM1 can be assembled into oligomers through intermolecular interaction between its F3 lobe in FERM domain and one of the three NPXY motifs. Despite being embedded in FERM domain as F3 lobe, F3 module acts as a fully functional PH domain to interact with NPXY motif. The most salient feature of the study was that both PTB and PH domains are structurally and functionally comparable, suggesting that PTB domain is likely evolved from PH domain with polymorphic structural additions at its N-terminus. CONCLUSIONS A new β1A-strand of the PTB domain was discovered and new minimum structural requirement of PTB/PH domain for NPXY motif-binding was determined. Based on our data, a novel theory of structure, function and relationship of PTB, PH and FERM domains has been proposed, which extends the importance of the NPXY-PTB/PH interaction on the CSC signaling and/or other cell receptors with great potential pointing to new therapeutic strategies. GENERAL SIGNIFICANCE The study provides new insight into the structural characteristics of PTB/PH domains, essential structural elements of PTB/PH domain required for NPXY motif-binding, and function and relationship among PTB, PH and FERM domains.
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Affiliation(s)
- Jun Zhang
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA.
| | - Pallavi Dubey
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
| | - Akhil Padarti
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
| | - Aileen Zhang
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
| | - Rinkal Patel
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
| | - Vipulkumar Patel
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
| | - David Cistola
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
| | - Ahmed Badr
- Department of Biomedical Sciences, Texas Tech University Health Sciences Center El Paso, El Paso, TX 79905, USA
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19
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Salzer U, Kostan J, Djinović-Carugo K. Deciphering the BAR code of membrane modulators. Cell Mol Life Sci 2017; 74:2413-2438. [PMID: 28243699 PMCID: PMC5487894 DOI: 10.1007/s00018-017-2478-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 01/25/2017] [Accepted: 01/27/2017] [Indexed: 01/06/2023]
Abstract
The BAR domain is the eponymous domain of the “BAR-domain protein superfamily”, a large and diverse set of mostly multi-domain proteins that play eminent roles at the membrane cytoskeleton interface. BAR domain homodimers are the functional units that peripherally associate with lipid membranes and are involved in membrane sculpting activities. Differences in their intrinsic curvatures and lipid-binding properties account for a large variety in membrane modulating properties. Membrane activities of BAR domains are further modified and regulated by intramolecular or inter-subunit domains, by intermolecular protein interactions, and by posttranslational modifications. Rather than providing detailed cell biological information on single members of this superfamily, this review focuses on biochemical, biophysical, and structural aspects and on recent findings that paradigmatically promote our understanding of processes driven and modulated by BAR domains.
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Affiliation(s)
- Ulrich Salzer
- Max F. Perutz Laboratories, Department of Medical Biochemistry, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Julius Kostan
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria
| | - Kristina Djinović-Carugo
- Max F. Perutz Laboratories, Department of Structural and Computational Biology, University of Vienna, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
- Department of Biochemistry, Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 119, 1000, Ljubljana, Slovenia.
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20
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Liu Z, Xiao T, Peng X, Li G, Hu F. APPLs: More than just adiponectin receptor binding proteins. Cell Signal 2017; 32:76-84. [PMID: 28108259 DOI: 10.1016/j.cellsig.2017.01.018] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 01/13/2017] [Accepted: 01/13/2017] [Indexed: 12/31/2022]
Abstract
APPLs (adaptor proteins containing the pleckstrin homology domain, phosphotyrosine binding domain and leucine zipper motif) are multifunctional adaptor proteins that bind to various membrane receptors, nuclear factors and signaling proteins to regulate many biological activities and processes, such as cell proliferation, chromatin remodeling, endosomal trafficking, cell survival, cell metabolism and apoptosis. APPL1, one of the APPL isoforms, was the first identified protein and interacts directly with adiponectin receptors to mediate adiponectin signaling to enhance lipid oxidation and glucose uptake. APPLs also act on insulin signaling pathways and are important mediators of insulin sensitization. Based on recent findings, this review highlights the critical roles of APPLs, particularly APPL1 and its isoform partner APPL2, in mediating adiponectin, insulin, endosomal trafficking and other signaling pathways. A deep understanding of APPLs and their related signaling pathways may potentially lead to therapeutic and interventional treatments for obesity, diabetes, cancer and neurodegenerative diseases.
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Affiliation(s)
- Zhuoying Liu
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center of Central South University, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Ting Xiao
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center of Central South University, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Xiaoyu Peng
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center of Central South University, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Guangdi Li
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center of Central South University, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China
| | - Fang Hu
- Department of Metabolism and Endocrinology, Metabolic Syndrome Research Center of Central South University, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China.
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21
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Tan Y, Xin X, Coffey FJ, Wiest DL, Dong LQ, Testa JR. Appl1 and Appl2 are Expendable for Mouse Development But Are Essential for HGF-Induced Akt Activation and Migration in Mouse Embryonic Fibroblasts. J Cell Physiol 2015; 231:1142-50. [PMID: 26445298 DOI: 10.1002/jcp.25211] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Accepted: 10/05/2015] [Indexed: 12/18/2022]
Abstract
Although Appl1 and Appl2 have been implicated in multiple cellular activities, we and others have found that Appl1 is dispensable for mouse embryonic development, suggesting that Appl2 can substitute for Appl1 during development. To address this possibility, we generated conditionally targeted Appl2 mice. We found that ubiquitous Appl2 knockout (Appl2-/-) mice, much like Appl1-/- mice, are viable and grow normally to adulthood. Intriguingly, when Appl1-/- mice were crossed with Appl2-/- mice, we found that homozygous Appl1;Appl2 double knockout (DKO) animals are also viable and grossly normal with regard to reproductive potential and postnatal growth. Appl2-null and DKO mice were found to exhibit altered red blood cell physiology, with erythrocytes from these mice generally being larger and having a more irregular shape than erythrocytes from wild type mice. Although Appl1/2 proteins have been previously shown to have a very strong interaction with phosphatidylinositol-3 kinase (Pi3k) in thymic T cells, Pi3k-Akt signaling and cellular differentiation was unaltered in thymocytes from Appl1;Appl2 (DKO) mice. However, Appl1/2-null mouse embryonic fibroblasts exhibited defects in HGF-induced Akt activation, migration, and invasion. Taken together, these data suggest that Appl1 and Appl2 are required for robust HGF cell signaling but are dispensable for embryonic development and reproduction.
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Affiliation(s)
- Yinfei Tan
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Xiaoban Xin
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Francis J Coffey
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - David L Wiest
- Blood Cell Development and Function Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
| | - Lily Q Dong
- Department of Cellular and Structural Biology, University of Texas Health Science Center at San Antonio, San Antonio, Texas
| | - Joseph R Testa
- Cancer Biology Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania
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22
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Prudente S, Jungtrakoon P, Marucci A, Ludovico O, Buranasupkajorn P, Mazza T, Hastings T, Milano T, Morini E, Mercuri L, Bailetti D, Mendonca C, Alberico F, Basile G, Romani M, Miccinilli E, Pizzuti A, Carella M, Barbetti F, Pascarella S, Marchetti P, Trischitta V, Di Paola R, Doria A. Loss-of-Function Mutations in APPL1 in Familial Diabetes Mellitus. Am J Hum Genet 2015; 97:177-85. [PMID: 26073777 DOI: 10.1016/j.ajhg.2015.05.011] [Citation(s) in RCA: 102] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 05/14/2015] [Indexed: 12/29/2022] Open
Abstract
Diabetes mellitus is a highly heterogeneous disorder encompassing several distinct forms with different clinical manifestations including a wide spectrum of age at onset. Despite many advances, the causal genetic defect remains unknown for many subtypes of the disease, including some of those forms with an apparent Mendelian mode of inheritance. Here we report two loss-of-function mutations (c.1655T>A [p.Leu552(∗)] and c.280G>A [p.Asp94Asn]) in the gene for the Adaptor Protein, Phosphotyrosine Interaction, PH domain, and leucine zipper containing 1 (APPL1) that were identified by means of whole-exome sequencing in two large families with a high prevalence of diabetes not due to mutations in known genes involved in maturity onset diabetes of the young (MODY). APPL1 binds to AKT2, a key molecule in the insulin signaling pathway, thereby enhancing insulin-induced AKT2 activation and downstream signaling leading to insulin action and secretion. Both mutations cause APPL1 loss of function. The p.Leu552(∗) alteration totally abolishes APPL1 protein expression in HepG2 transfected cells and the p.Asp94Asn alteration causes significant reduction in the enhancement of the insulin-stimulated AKT2 and GSK3β phosphorylation that is observed after wild-type APPL1 transfection. These findings-linking APPL1 mutations to familial forms of diabetes-reaffirm the critical role of APPL1 in glucose homeostasis.
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Affiliation(s)
- Sabrina Prudente
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy.
| | - Prapaporn Jungtrakoon
- Research Division, Joslin Diabetes Center, Boston, MA 02215, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Antonella Marucci
- Research Unit of Diabetes and Endocrine Diseases, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Ornella Ludovico
- Research Unit of Diabetes and Endocrine Diseases, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Patinut Buranasupkajorn
- Research Division, Joslin Diabetes Center, Boston, MA 02215, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Tommaso Mazza
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Timothy Hastings
- Research Division, Joslin Diabetes Center, Boston, MA 02215, USA
| | - Teresa Milano
- Department of Biochemical Sciences, Sapienza University, 00185 Rome, Italy
| | - Eleonora Morini
- Research Unit of Diabetes and Endocrine Diseases, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Luana Mercuri
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Diego Bailetti
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy; Department of Experimental Medicine, Sapienza University, 00161 Rome, Italy
| | | | - Federica Alberico
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Giorgio Basile
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy; Department of Experimental Medicine, Sapienza University, 00161 Rome, Italy
| | - Marta Romani
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Elide Miccinilli
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Antonio Pizzuti
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy; Department of Experimental Medicine, Sapienza University, 00161 Rome, Italy
| | - Massimo Carella
- Unit of Medical Genetics, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Fabrizio Barbetti
- Laboratory of Mendelian Diabetes, Bambino Gesù Childrens' Hospital, 00165 Rome, Italy; Department of Experimental Medicine and Surgery, University of Tor Vergata, 00133 Rome, Italy
| | - Stefano Pascarella
- Department of Biochemical Sciences, Sapienza University, 00185 Rome, Italy
| | - Piero Marchetti
- Department of Clinical and Experimental Medicine, University of Pisa, 56127 Pisa, Italy
| | - Vincenzo Trischitta
- Mendel Laboratory, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy; Research Unit of Diabetes and Endocrine Diseases, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy; Department of Experimental Medicine, Sapienza University, 00161 Rome, Italy
| | - Rosa Di Paola
- Research Unit of Diabetes and Endocrine Diseases, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni Rotondo, Italy
| | - Alessandro Doria
- Research Division, Joslin Diabetes Center, Boston, MA 02215, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
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23
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Karlsen ML, Thorsen TS, Johner N, Ammendrup-Johnsen I, Erlendsson S, Tian X, Simonsen JB, Høiberg-Nielsen R, Christensen NM, Khelashvili G, Streicher W, Teilum K, Vestergaard B, Weinstein H, Gether U, Arleth L, Madsen KL. Structure of Dimeric and Tetrameric Complexes of the BAR Domain Protein PICK1 Determined by Small-Angle X-Ray Scattering. Structure 2015; 23:1258-1270. [PMID: 26073603 DOI: 10.1016/j.str.2015.04.020] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/20/2015] [Accepted: 04/23/2015] [Indexed: 11/15/2022]
Abstract
PICK1 is a neuronal scaffolding protein containing a PDZ domain and an auto-inhibited BAR domain. BAR domains are membrane-sculpting protein modules generating membrane curvature and promoting membrane fission. Previous data suggest that BAR domains are organized in lattice-like arrangements when stabilizing membranes but little is known about structural organization of BAR domains in solution. Through a small-angle X-ray scattering (SAXS) analysis, we determine the structure of dimeric and tetrameric complexes of PICK1 in solution. SAXS and biochemical data reveal a strong propensity of PICK1 to form higher-order structures, and SAXS analysis suggests an offset, parallel mode of BAR-BAR oligomerization. Furthermore, unlike accessory domains in other BAR domain proteins, the positioning of the PDZ domains is flexible, enabling PICK1 to perform long-range, dynamic scaffolding of membrane-associated proteins. Together with functional data, these structural findings are compatible with a model in which oligomerization governs auto-inhibition of BAR domain function.
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Affiliation(s)
- Morten L Karlsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Thor S Thorsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Niklaus Johner
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, Room E-509, 1300 York Avenue, 10065, New York City, NY, USA
| | - Ina Ammendrup-Johnsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Simon Erlendsson
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark.,Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Xinsheng Tian
- Biostructural Research, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen Ø, Denmark
| | - Jens B Simonsen
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Rasmus Høiberg-Nielsen
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Nikolaj M Christensen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - George Khelashvili
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, Room E-509, 1300 York Avenue, 10065, New York City, NY, USA
| | - Werner Streicher
- NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Kaare Teilum
- Structural Biology and NMR Laboratory, Department of Biology, Faculty of Science, University of Copenhagen, Ole Maaløes Vej 5, 2200 Copenhagen N, Denmark
| | - Bente Vestergaard
- Biostructural Research, Department of Drug Design and Pharmacology, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen Ø, Denmark
| | - Harel Weinstein
- Department of Physiology and Biophysics, Weill Cornell Medical College, Cornell University, Room E-509, 1300 York Avenue, 10065, New York City, NY, USA
| | - Ulrik Gether
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
| | - Lise Arleth
- Structural Biophysics, Niels Bohr Institute, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen Ø, Denmark
| | - Kenneth L Madsen
- Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Department of Neuroscience and Pharmacology, Faculty of Health and Medical Sciences, The Panum Institute 18.6, University of Copenhagen, 2200 Copenhagen N, Denmark
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24
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Suetsugu S, Kurisu S, Takenawa T. Dynamic shaping of cellular membranes by phospholipids and membrane-deforming proteins. Physiol Rev 2014; 94:1219-48. [PMID: 25287863 DOI: 10.1152/physrev.00040.2013] [Citation(s) in RCA: 150] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
All cellular compartments are separated from the external environment by a membrane, which consists of a lipid bilayer. Subcellular structures, including clathrin-coated pits, caveolae, filopodia, lamellipodia, podosomes, and other intracellular membrane systems, are molded into their specific submicron-scale shapes through various mechanisms. Cells construct their micro-structures on plasma membrane and execute vital functions for life, such as cell migration, cell division, endocytosis, exocytosis, and cytoskeletal regulation. The plasma membrane, rich in anionic phospholipids, utilizes the electrostatic nature of the lipids, specifically the phosphoinositides, to form interactions with cytosolic proteins. These cytosolic proteins have three modes of interaction: 1) electrostatic interaction through unstructured polycationic regions, 2) through structured phosphoinositide-specific binding domains, and 3) through structured domains that bind the membrane without specificity for particular phospholipid. Among the structured domains, there are several that have membrane-deforming activity, which is essential for the formation of concave or convex membrane curvature. These domains include the amphipathic helix, which deforms the membrane by hemi-insertion of the helix with both hydrophobic and electrostatic interactions, and/or the BAR domain superfamily, known to use their positively charged, curved structural surface to deform membranes. Below the membrane, actin filaments support the micro-structures through interactions with several BAR proteins as well as other scaffold proteins, resulting in outward and inward membrane micro-structure formation. Here, we describe the characteristics of phospholipids, and the mechanisms utilized by phosphoinositides to regulate cellular events. We then summarize the precise mechanisms underlying the construction of membrane micro-structures and their involvements in physiological and pathological processes.
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Affiliation(s)
- Shiro Suetsugu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Shusaku Kurisu
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
| | - Tadaomi Takenawa
- Graduate School of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Nara, Japan; Biosignal Research Center, Kobe University, Kobe, Hyogo, Japan; and Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
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25
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Cheng KKY, Zhu W, Chen B, Wang Y, Wu D, Sweeney G, Wang B, Lam KSL, Xu A. The adaptor protein APPL2 inhibits insulin-stimulated glucose uptake by interacting with TBC1D1 in skeletal muscle. Diabetes 2014; 63:3748-58. [PMID: 24879834 DOI: 10.2337/db14-0337] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Insulin stimulates glucose uptake by promoting the trafficking of GLUT4 to the plasma membrane in muscle cells, and impairment of this insulin action contributes to hyperglycemia in type 2 diabetes. The adaptor protein APPL1 potentiates insulin-stimulated Akt activation and downstream actions. However, the physiological functions of APPL2, a close homolog of APPL1, in regulating glucose metabolism remain elusive. We show that insulin-evoked plasma membrane recruitment of GLUT4 and glucose uptake are impaired by APPL2 overexpression but enhanced by APPL2 knockdown. Likewise, conditional deletion of APPL2 in skeletal muscles enhances insulin sensitivity, leading to an improvement in glucose tolerance. We identified the Rab-GTPase-activating protein TBC1D1 as an interacting partner of APPL2. Insulin stimulates TBC1D1 phosphorylation on serine 235, leading to enhanced interaction with the BAR domain of APPL2, which in turn suppresses insulin-evoked TBC1D1 phosphorylation on threonine 596 in cultured myotubes and skeletal muscle. Substitution of serine 235 with alanine diminishes APPL2-mediated inhibition on insulin-dependent TBC1D1 phosphorylation on threonine 596 and the suppressive effects of TBC1D1 on insulin-induced glucose uptake and GLUT4 translocation to the plasma membrane in cultured myotubes. Therefore, the APPL2-TBC1D1 interaction is a key step to fine tune insulin-stimulated glucose uptake by regulating the membrane recruitment of GLUT4 in skeletal muscle.
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Affiliation(s)
- Kenneth K Y Cheng
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong
| | - Weidong Zhu
- Department of Medicine, The University of Hong Kong, Hong Kong
| | - Bin Chen
- Department of Medicine, The University of Hong Kong, Hong Kong
| | - Yu Wang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Pharmacology & Pharmacy, The University of Hong Kong, Hong Kong
| | - Donghai Wu
- The Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Gary Sweeney
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Baile Wang
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong
| | - Karen S L Lam
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong
| | - Aimin Xu
- State Key Laboratory of Pharmaceutical Biotechnology, The University of Hong Kong, Hong Kong Department of Medicine, The University of Hong Kong, Hong Kong Department of Pharmacology & Pharmacy, The University of Hong Kong, Hong Kong
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26
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Petoukhov MV, Weissenhorn W, Svergun DI. Endophilin-A1 BAR domain interaction with arachidonyl CoA. Front Mol Biosci 2014; 1:20. [PMID: 25988161 PMCID: PMC4428356 DOI: 10.3389/fmolb.2014.00020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 10/08/2014] [Indexed: 11/13/2022] Open
Abstract
Endophilin-A1 belongs to the family of BAR domain containing proteins that catalyze membrane remodeling processes via sensing, inducing and stabilizing membrane curvature. We show that the BAR domain of endophilin-A1 binds arachidonic acid and molds its coenzyme A (CoA) activated form, arachidonyl-CoA into a defined structure. We studied low resolution structures of endophilin-A1-BAR and its complex with arachidonyl-CoA in solution using synchrotron small-angle X-ray scattering (SAXS). The free endophilin-A1-BAR domain is shown to be dimeric at lower concentrations but builds tetramers and higher order complexes with increasing concentrations. Extensive titration SAXS studies revealed that the BAR domain produces a homogenous complex with the lipid micelles. The structural model of the complexes revealed two arachidonyl-CoA micelles bound to the distal arms of an endophilin-A1-BAR dimer. Intriguingly, the radius of the bound micelles significantly decreases compared to that of the free micelles, and this structural result may provide hints on the potential biological relevance of the endophilin-A1-BAR interaction with arachidonyl CoA.
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Affiliation(s)
- Maxim V. Petoukhov
- Hamburg Unit, European Molecular Biology Laboratory c/o DESYHamburg, Germany
| | - Winfried Weissenhorn
- Unit of Virus Host Cell Interactions, University Grenoble AlpesGrenoble, France
- Unit of Virus Host Cell Interactions, Centre National de la Recherche ScientifiqueGrenoble, France
| | - Dmitri I. Svergun
- Hamburg Unit, European Molecular Biology Laboratory c/o DESYHamburg, Germany
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27
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Pang X, Fan J, Zhang Y, Zhang K, Gao B, Ma J, Li J, Deng Y, Zhou Q, Egelman EH, Hsu VW, Sun F. A PH domain in ACAP1 possesses key features of the BAR domain in promoting membrane curvature. Dev Cell 2014; 31:73-86. [PMID: 25284369 PMCID: PMC4198613 DOI: 10.1016/j.devcel.2014.08.020] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 08/12/2014] [Accepted: 08/21/2014] [Indexed: 11/29/2022]
Abstract
The BAR (Bin-Amphiphysin-Rvs) domain undergoes dimerization to produce a curved protein structure, which superimposes onto membrane through electrostatic interactions to sense and impart membrane curvature. In some cases, a BAR domain also possesses an amphipathic helix that inserts into the membrane to induce curvature. ACAP1 (Arfgap with Coil coil, Ankyrin repeat, and PH domain protein 1) contains a BAR domain. Here, we show that this BAR domain can neither bind membrane nor impart curvature, but instead requires a neighboring PH (Pleckstrin Homology) domain to achieve these functions. Specific residues within the PH domain are responsible for both membrane binding and curvature generation. The BAR domain adjacent to the PH domain instead interacts with the BAR domains of neighboring ACAP1 proteins to enable clustering at the membrane. Thus, we have uncovered the molecular basis for an unexpected and unconventional collaboration between PH and BAR domains in membrane bending.
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Affiliation(s)
- Xiaoyun Pang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Fan
- Department of Physics and Materials Science, City University of Hong Kong, Hong Kong 999077, China
| | - Yan Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Kai Zhang
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Bingquan Gao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jun Ma
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Li
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA
| | - Yuchen Deng
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiangjun Zhou
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
| | - Edward H Egelman
- Department of Biochemistry and Molecular Genetics, University of Virginia, Charlottesville, VA 22908, USA
| | - Victor W Hsu
- Division of Rheumatology, Immunology and Allergy, Brigham and Women's Hospital, Boston, MA 02115, USA; Department of Medicine, Harvard Medical School, Boston, MA 02115, USA.
| | - Fei Sun
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China; Center for Biological Imaging, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China.
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28
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Cheng KKY, Lam KSL, Wang B, Xu A. Signaling mechanisms underlying the insulin-sensitizing effects of adiponectin. Best Pract Res Clin Endocrinol Metab 2014; 28:3-13. [PMID: 24417941 DOI: 10.1016/j.beem.2013.06.006] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Adiponectin is an insulin-sensitizing adipokine with protective effects against a cluster of obesity-related metabolic and cardiovascular disorders. The adipokine exerts its insulin-sensitizing effects by alleviation of obesity-induced ectopic lipid accumulation, lipotoxicity and chronic inflammation, as well as by direct cross-talk with insulin signaling cascades. Adiponectin and insulin signaling pathways converge at the adaptor protein APPL1. On the one hand, APPL1 interacts with adiponectin receptors and mediates both metabolic and vascular actions of adiponectin through activation of AMP-activated protein kinase and p38 MAP kinase. On the other hand, APPL1 potentiates both the actions and secretion of insulin by fine-tuning the Akt activity in multiple insulin target tissues. In obese animals, reduced APPL1 expression contributes to both insulin resistance and defective insulin secretion. This review summarizes recent advances on the molecular mechanisms by which adiponectin sensitizes insulin actions, and discusses the roles of APPL1 in regulating both adiponectin and insulin signaling cascades.
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Affiliation(s)
- Kenneth K Y Cheng
- Department of Medicine, The University of Hong Kong, Hong Kong; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong
| | - Karen S L Lam
- Department of Medicine, The University of Hong Kong, Hong Kong; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong
| | - Baile Wang
- Department of Medicine, The University of Hong Kong, Hong Kong
| | - Aimin Xu
- Department of Medicine, The University of Hong Kong, Hong Kong; Research Centre of Heart, Brain, Hormone and Healthy Aging, The University of Hong Kong, Hong Kong; Department of Pharmacology & Pharmacy, The University of Hong Kong, Hong Kong.
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An Analytical Approach to Vibration Analysis of Beams with Variable Properties. ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING 2013. [DOI: 10.1007/s13369-013-0898-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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TRAF6-mediated ubiquitination of APPL1 enhances hepatic actions of insulin by promoting the membrane translocation of Akt. Biochem J 2013; 455:207-16. [DOI: 10.1042/bj20130760] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The adaptor protein APPL1 undergoes ubiquitination upon insulin stimulation in a TRAF6-dependent manner. Abrogation of APPL1 ubiquitination blocks insulin-evoked membrane localization of the APPL1–Akt complex, leading to impaired insulin actions on Akt activation and suppression of hepatic glucose production.
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Liu W, Boggon TJ. Cocrystal structure of the ICAP1 PTB domain in complex with a KRIT1 peptide. Acta Crystallogr Sect F Struct Biol Cryst Commun 2013; 69:494-8. [PMID: 23695561 DOI: 10.1107/s1744309113010762] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 04/19/2013] [Indexed: 11/11/2022]
Abstract
Integrin cytoplasmic domain-associated protein-1 (ICAP1) is a suppressor of integrin activation and directly binds to the cytoplasmic tail of β1 integrins; its binding suppresses integrin activation by competition with talin. Krev/Rap1 interaction trapped-1 (KRIT1) releases ICAP1 suppression of integrin activation by sequestering ICAP1 away from integrin cytoplasmic tails. Here, the cocrystal structure of the PTB domain of ICAP1 in complex with a 29-amino-acid fragment (residues 170-198) of KRIT1 is presented to 1.7 Å resolution [the resolution at which 〈I/σ(I)〉 = 2.9 was 1.83 Å]. In previous studies, the structure of ICAP1 with integrin β1 was determined to 3.0 Å resolution and that of ICAP1 with the N-terminal portion of KRIT1 (residues 1-198) was determined to 2.54 Å resolution; therefore, this study provides the highest resolution structure yet of ICAP1 and allows further detailed analysis of the interaction of ICAP1 with its minimal binding region in KRIT1.
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Affiliation(s)
- Weizhi Liu
- Department of Pharmacology, Yale University School of Medicine, New Haven, CT 06520, USA.
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King GJ, Stöckli J, Hu SH, Winnen B, Duprez WGA, Meoli CC, Junutula JR, Jarrott RJ, James DE, Whitten AE, Martin JL. Membrane curvature protein exhibits interdomain flexibility and binds a small GTPase. J Biol Chem 2012; 287:40996-1006. [PMID: 23055524 DOI: 10.1074/jbc.m112.349803] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The APPL1 and APPL2 proteins (APPL (adaptor protein, phosphotyrosine interaction, pleckstrin homology (PH) domain, and leucine zipper-containing protein)) are localized to their own endosomal subcompartment and interact with a wide range of proteins and small molecules at the cell surface and in the nucleus. They play important roles in signal transduction through their ability to act as Rab effectors. (Rabs are a family of Ras GTPases involved in membrane trafficking.) Both APPL1 and APPL2 comprise an N-terminal membrane-curving BAR (Bin-amphiphysin-Rvs) domain linked to a PH domain and a C-terminal phosphotyrosine-binding domain. The structure and interactions of APPL1 are well characterized, but little is known about APPL2. Here, we report the crystal structure and low resolution solution structure of the BARPH domains of APPL2. We identify a previously undetected hinge site for rotation between the two domains and speculate that this motion may regulate APPL2 functions. We also identified Rab binding partners of APPL2 and show that these differ from those of APPL1, suggesting that APPL-Rab interaction partners have co-evolved over time. Isothermal titration calorimetry data reveal the interaction between APPL2 and Rab31 has a K(d) of 140 nM. Together with other biophysical data, we conclude the stoichiometry of the complex is 2:2.
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Affiliation(s)
- Gordon J King
- Institute for Molecular Bioscience, University of Queensland, Brisbane, Queensland 4072, Australia
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33
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Broussard JA, Lin WH, Majumdar D, Anderson B, Eason B, Brown CM, Webb DJ. The endosomal adaptor protein APPL1 impairs the turnover of leading edge adhesions to regulate cell migration. Mol Biol Cell 2012; 23:1486-99. [PMID: 22379109 PMCID: PMC3327316 DOI: 10.1091/mbc.e11-02-0124] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Cell migration is a complex process that requires the integration of signaling events that occur in distinct locations within the cell. Adaptor proteins, which can localize to different subcellular compartments, where they bring together key signaling proteins, are emerging as attractive candidates for controlling spatially coordinated processes. However, their function in regulating cell migration is not well understood. In this study, we demonstrate a novel role for the adaptor protein containing a pleckstrin-homology (PH) domain, phosphotyrosine-binding (PTB) domain, and leucine zipper motif 1 (APPL1) in regulating cell migration. APPL1 impairs migration by hindering the turnover of adhesions at the leading edge of cells. The mechanism by which APPL1 regulates migration and adhesion dynamics is by inhibiting the activity of the serine/threonine kinase Akt at the cell edge and within adhesions. In addition, APPL1 significantly decreases the tyrosine phosphorylation of Akt by the nonreceptor tyrosine kinase Src, which is critical for Akt-mediated cell migration. Thus, our results demonstrate an important new function for APPL1 in regulating cell migration and adhesion turnover through a mechanism that depends on Src and Akt. Moreover, our data further underscore the importance of adaptor proteins in modulating the flow of information through signaling pathways.
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Affiliation(s)
- Joshua A Broussard
- Department of Biological Sciences and Vanderbilt Kennedy Center for Research on Human Development, Nashville, TN 37235, USA
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34
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Wang Y, Cheng KK, Lam KS, Wu D, Wang Y, Huang Y, Vanhoutte PM, Sweeney G, Li Y, Xu A. APPL1 counteracts obesity-induced vascular insulin resistance and endothelial dysfunction by modulating the endothelial production of nitric oxide and endothelin-1 in mice. Diabetes 2011; 60:3044-54. [PMID: 21926268 PMCID: PMC3198090 DOI: 10.2337/db11-0666] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
OBJECTIVE Insulin stimulates both nitric oxide (NO)-dependent vasodilation and endothelin-1 (ET-1)-dependent vasoconstriction. However, the cellular mechanisms that control the dual vascular effects of insulin remain unclear. This study aimed to investigate the roles of the multidomain adaptor protein APPL1 in modulating vascular actions of insulin in mice and in endothelial cells. RESEARCH DESIGN AND METHODS Both APPL1 knockout mice and APPL1 transgenic mice were generated to evaluate APPL1's physiological roles in regulating vascular reactivity and insulin signaling in endothelial cells. RESULTS Insulin potently induced NO-dependent relaxations in mesenteric arteries of 8-week-old mice, whereas this effect of insulin was progressively impaired with ageing or upon development of obesity induced by high-fat diet. Transgenic expression of APPL1 prevented age- and obesity-induced impairment in insulin-induced vasodilation and reversed obesity-induced augmentation in insulin-evoked ET-1-dependent vasoconstriction. By contrast, genetic disruption of APPL1 shifted the effects of insulin from vasodilation to vasoconstriction. At the molecular level, insulin-elicited activation of protein kinase B (Akt) and endothelial NO synthase and production of NO were enhanced in APPL1 transgenic mice but were abrogated in APPL1 knockout mice. Conversely, insulin-induced extracellular signal-related kinase (ERK)1/2 phosphorylation and ET-1 expression was augmented in APPL1 knockout mice but was diminished in APPL1 transgenic mice. In endothelial cells, APPL1 potentiated insulin-stimulated Akt activation by competing with the Akt inhibitor Tribbles 3 (TRB3) and suppressed ERK1/2 signaling by altering the phosphorylation status of its upstream kinase Raf-1. CONCLUSIONS APPL1 plays a key role in coordinating the vasodilator and vasoconstrictor effects of insulin by modulating Akt-dependent NO production and ERK1/2-mediated ET-1 secretion in the endothelium.
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Affiliation(s)
- Yi Wang
- Department of Medicine, Division of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
- Department of Medicine, the University of Hong Kong, Hong Kong
| | | | - Karen S.L. Lam
- Department of Medicine, the University of Hong Kong, Hong Kong
| | - Donghai Wu
- Key Laboratory of Regenerative Biology, Guangzhou Institute of Biomedicine and Health, Chinese Academy of Sciences, Guangzhou, China
| | - Yu Wang
- Department of Pharmacology and Pharmacy, the University of Hong Kong, Hong Kong
| | - Yu Huang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences and School Of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong
| | - Paul M. Vanhoutte
- Department of Pharmacology and Pharmacy, the University of Hong Kong, Hong Kong
| | - Gary Sweeney
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Yiming Li
- Department of Medicine, Division of Endocrinology and Metabolism, Huashan Hospital, Shanghai Medical College, Fudan University, Shanghai, China
| | - Aimin Xu
- Department of Medicine, the University of Hong Kong, Hong Kong
- Department of Pharmacology and Pharmacy, the University of Hong Kong, Hong Kong
- Corresponding authors: Aimin Xu, , and Yiming Li,
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Pirozzi F, Di Raimo FR, Zanni G, Bertini E, Billuart P, Tartaglione T, Tabolacci E, Brancaccio A, Neri G, Chiurazzi P. Insertion of 16 amino acids in the BAR domain of the oligophrenin 1 protein causes mental retardation and cerebellar hypoplasia in an Italian family. Hum Mutat 2011; 32:E2294-307. [PMID: 21796728 DOI: 10.1002/humu.21567] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2010] [Accepted: 07/07/2011] [Indexed: 11/10/2022]
Abstract
We observed a three-generation family with two maternal cousins and an uncle affected by mental retardation (MR) with cerebellar hypoplasia. X-linked inheritance and the presence of cerebellar malformation suggested a mutation in the OPHN1 gene. In fact, mutational screening revealed a 2-bp deletion that abolishes a donor splicing site, resulting in the inclusion of the initial 48 nucleotides of intron 7 in the mRNA. This mutation determines the production of a mutant oligophrenin 1 protein with 16 extra amino acids inserted in-frame in the N-terminal BAR (Bin1/amphiphysin/Rvs167) domain. This is the first case of a mutation in OPHN1 that does not result in the production of a truncated protein or in its complete loss. OPHN1 (ARHGAP41) encodes a GTPase-activating (GAP) protein belonging to the GRAF subfamily characterized by an N-terminal BAR domain, followed by a pleckstrin-homology (PH) domain and the GAP domain. GRAF proteins play a role in endocytosis and are supposed to dimerize via their BAR domain, that induces membrane curvature. The extra 16 amino acids cause the insertion of 4.4 turns in the third alpha-helix of the BAR domain and apparently impair the protein function. In fact, the clinical phenotype of these patients is identical to that of patients with loss-of-function mutations.
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36
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Qualmann B, Koch D, Kessels MM. Let's go bananas: revisiting the endocytic BAR code. EMBO J 2011; 30:3501-15. [PMID: 21878992 DOI: 10.1038/emboj.2011.266] [Citation(s) in RCA: 182] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Accepted: 07/15/2011] [Indexed: 12/27/2022] Open
Abstract
Against the odds of membrane resistance, members of the BIN/Amphiphysin/Rvs (BAR) domain superfamily shape membranes and their activity is indispensable for a plethora of life functions. While crystal structures of different BAR dimers advanced our understanding of membrane shaping by scaffolding and hydrophobic insertion mechanisms considerably, especially life-imaging techniques and loss-of-function studies of clathrin-mediated endocytosis with its gradually increasing curvature show that the initial idea that solely BAR domain curvatures determine their functions is oversimplified. Diagonal placing, lateral lipid-binding modes, additional lipid-binding modules, tilde shapes and formation of macromolecular lattices with different modes of organisation and arrangement increase versatility. A picture emerges, in which BAR domain proteins create macromolecular platforms, that recruit and connect different binding partners and ensure the connection and coordination of the different events during the endocytic process, such as membrane invagination, coat formation, actin nucleation, vesicle size control, fission, detachment and uncoating, in time and space, and may thereby offer mechanistic explanations for how coordination, directionality and effectiveness of a complex process with several steps and key players can be achieved.
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Affiliation(s)
- Britta Qualmann
- Institute for Biochemistry I, University Hospital Jena-Friedrich Schiller University Jena, Germany.
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37
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Urbanska A, Sadowski L, Kalaidzidis Y, Miaczynska M. Biochemical characterization of APPL endosomes: the role of annexin A2 in APPL membrane recruitment. Traffic 2011; 12:1227-41. [PMID: 21645192 PMCID: PMC3380557 DOI: 10.1111/j.1600-0854.2011.01226.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
APPL endosomes are a recently identified subpopulation of early endosomes characterized by the presence of two homologous Rab5 effector proteins APPL1 and APPL2. They exhibit only limited colocalization with EEA1, another Rab5 effector and a marker of the canonical early endosomes. Although APPL endosomes appear to play important roles in cargo trafficking and signal transduction, their protein composition and biochemical properties remain largely unknown. Here we employed membrane fractionation methods to characterize APPL endosomes biochemically. We demonstrate that they represent heterogeneous membrane structures which can be discriminated from the canonical EEA1-positive early endosomes by their partly different physical properties and a distinct migration pattern in the continuous density gradients. In search for other potential markers of APPL endosomes we identified Annexin A2 as an interacting partner of both APPL1 and APPL2. Annexin A2 is a Ca2+ and phosphatidylinositol 4,5-bisphosphate binding protein, previously implicated in several endocytic steps. We show that Annexin A2 co-fractionates and colocalizes with APPL endosomes. Moreover, silencing of its expression causes solubilization of APPL2 from endosomes. Although Annexin A2 is not an exclusive marker of APPL endosomes, our data suggest that it has an important function in membrane recruitment of APPL proteins, acting in parallel to Rab5.
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Affiliation(s)
- Anna Urbanska
- International Institute of Molecular and Cell Biology, Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, 4 Ks. Trojdena Street, 02-109 Warsaw, Poland
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Lyman E, Cui H, Voth GA. Reconstructing protein remodeled membranes in molecular detail from mesoscopic models. Phys Chem Chem Phys 2011; 13:10430-6. [PMID: 21503332 DOI: 10.1039/c0cp02978e] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present a method for "inverse coarse graining," rebuilding a higher resolution model from a lower resolution one, in order to rebuild protein coats for remodeled membranes of complex topology. The specific case of membrane remodeling by N-BAR domain containing proteins is considered here, although the overall method is general and thus applicable to other membrane remodeling phenomena. Our approach begins with a previously developed, discretized mesoscopic continuum membrane model (EM2) which has been shown to capture the reticulated membrane topologies often observed for N-BAR/liposome systems by electron microscopy (EM). The information in the EM2 model-directions of the local curvatures and a low resolution sample of the membrane surface-is then used to construct a coarse-grained (CG) system with one site per lipid and 26 sites per protein. We demonstrate the approach on pieces of EM2 structures with three different topologies that have been observed by EM: A tubule, a "Y" junction, and a torus. We show that the approach leads to structures that are stable under subsequent constant temperature CG simulation, and end by considering the future application of the methodology as a hybrid approach that combines experimental information with computer modeling.
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Affiliation(s)
- Edward Lyman
- Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, and Computation Institute, University of Chicago, 5735 S Ellis Ave., Chicago, IL 60637, USA
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An APPL1/Akt signaling complex regulates dendritic spine and synapse formation in hippocampal neurons. Mol Cell Neurosci 2011; 46:633-44. [PMID: 21236345 DOI: 10.1016/j.mcn.2011.01.003] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 11/04/2010] [Accepted: 01/04/2011] [Indexed: 01/16/2023] Open
Abstract
The formation and plasticity of dendritic spines and synapses, which are poorly understood on a molecular level, are critical for cognitive functions, such as learning and memory. The adaptor protein containing a PH domain, PTB domain, and leucine zipper motif (APPL1) is emerging as a critical regulator of various cellular processes in non-neuronal cells, but its function in the nervous system is not well understood. Here, we show that APPL1 localizes to dendritic spines and synapses and regulates the development of these structures in hippocampal neurons. Knockdown of endogenous APPL1 using siRNA led to a significant decrease in the number of spines as well as synapses and this defect could be rescued by expression of siRNA-resistant APPL1. Expression of exogenous APPL1 increased the spine and synaptic density and the amount of surface GluR1-containing α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptors (AMPARs). Deletion of the C-terminal phosphotyrosine binding domain of APPL1, which binds the serine/threonine kinase Akt, resulted in a significant decrease in the spine and synaptic density, suggesting a role for Akt in regulating the development of these structures. Consistent with this, knockdown of Akt with siRNA or expression of dominant negative Akt led to a dramatic decrease in spine and synapse formation. In addition, APPL1 increased the amount of active Akt in spines and synapses and the effects of APPL1 on these structures were dependent on Akt, indicating that Akt is an effector of APPL1 in the regulation of these processes. Moreover, APPL1 signaling modulates spine and synapse formation through p21-activated kinase (PAK). Thus, our results indicate that APPL1 signaling through Akt and PAK is critical for spine and synaptic development and point to a role for APPL1 and its effectors in regulating cognitive function.
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40
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Dias JA, Mahale SD, Nechamen CA, Davydenko O, Thomas RM, Ulloa-Aguirre A. Emerging roles for the FSH receptor adapter protein APPL1 and overlap of a putative 14-3-3τ interaction domain with a canonical G-protein interaction site. Mol Cell Endocrinol 2010; 329:17-25. [PMID: 20600589 PMCID: PMC2946492 DOI: 10.1016/j.mce.2010.05.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/05/2010] [Revised: 05/20/2010] [Accepted: 05/20/2010] [Indexed: 12/13/2022]
Abstract
The interaction of cytoplasmic proteins with intracellular domains of membrane receptors can occur at several opportunities, including: during biosynthesis, while in membrane residency and during internalization and recycling following ligand binding. Since the initial discovery that it interacts with the FSH receptor (FSHR) together with additional members of a potential signaling complex, APPL1 has been shown to interact with a variety of membrane receptors. Recent subcellular localizations of APPL1 place it in dynamic and varied venues in the cell, including at the cell membrane, the nucleus and the early endosomes. Another adapter protein family the 14-3-3 proteins, are largely recognized as binding to phosphorylation sites but recent work demonstrated that in the case of FSHR, the 14-3-3 site overlaps with the canonical G-protein binding site. G-proteins appear to sample the environment and exchange between the membrane and intracellular locales and this binding could be mediated by or modulated by receptor interactions at the 14-3-3 binding site. Observations that multiple proteins can interact with cytoplasmic domains of GPCRs leads to the inescapable conclusion that either the interactions occur via orderly replacement or exchange, or that receptors are simultaneously occupied by a variety of adapters and effectors or even that oligomers of dimeric GPCRs provide for platforms that can simultaneously interact with effectors and adaptors.
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Affiliation(s)
- James A Dias
- Wadsworth Center, New York State Dept of Health, Albany, NY, United States.
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41
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Chial HJ, Lenart P, Chen YQ. APPL proteins FRET at the BAR: direct observation of APPL1 and APPL2 BAR domain-mediated interactions on cell membranes using FRET microscopy. PLoS One 2010; 5:e12471. [PMID: 20814572 PMCID: PMC2930004 DOI: 10.1371/journal.pone.0012471] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2009] [Accepted: 07/25/2010] [Indexed: 01/05/2023] Open
Abstract
BACKGROUND Human APPL1 and APPL2 are homologous RAB5 effectors whose binding partners include a diverse set of transmembrane receptors, signaling proteins, and phosphoinositides. APPL proteins associate dynamically with endosomal membranes and are proposed to function in endosome-mediated signaling pathways linking the cell surface to the cell nucleus. APPL proteins contain an N-terminal Bin/Amphiphysin/Rvs (BAR) domain, a central pleckstrin homology (PH) domain, and a C-terminal phosphotyrosine binding (PTB) domain. Previous structural and biochemical studies have shown that the APPL BAR domains mediate homotypic and heterotypic APPL-APPL interactions and that the APPL1 BAR domain forms crescent-shaped dimers. Although previous studies have shown that APPL minimal BAR domains associate with curved cell membranes, direct interaction between APPL BAR domains on cell membranes in vivo has not been reported. METHODOLOGY Herein, we used a laser-scanning confocal microscope equipped with a spectral detector to carry out fluorescence resonance energy transfer (FRET) experiments with cyan fluorescent protein/yellow fluorescent protein (CFP/YFP) FRET donor/acceptor pairs to examine interactions between APPL minimal BAR domains at the subcellular level. This comprehensive approach enabled us to evaluate FRET levels in a single cell using three methods: sensitized emission, standard acceptor photobleaching, and sequential acceptor photobleaching. We also analyzed emission spectra to address an outstanding controversy regarding the use of CFP donor/YFP acceptor pairs in FRET acceptor photobleaching experiments, based on reports that photobleaching of YFP converts it into a CFP-like species. CONCLUSIONS All three methods consistently showed significant FRET between APPL minimal BAR domain FRET pairs, indicating that they interact directly in a homotypic (i.e., APPL1-APPL1 and APPL2-APPL2) and heterotypic (i.e., APPL1-APPL2) manner on curved cell membranes. Furthermore, the results of our experiments did not show photoconversion of YFP into a CFP-like species following photobleaching, supporting the use of CFP donor/YFP acceptor FRET pairs in acceptor photobleaching studies.
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Affiliation(s)
- Heidi J Chial
- Department of Cancer Biology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, United States of America.
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42
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Masuda M, Mochizuki N. Structural characteristics of BAR domain superfamily to sculpt the membrane. Semin Cell Dev Biol 2010; 21:391-8. [DOI: 10.1016/j.semcdb.2010.01.010] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2009] [Revised: 01/07/2010] [Accepted: 01/08/2010] [Indexed: 11/28/2022]
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Gant-Branum RL, Broussard JA, Mahsut A, Webb DJ, McLean JA. Identification of phosphorylation sites within the signaling adaptor APPL1 by mass spectrometry. J Proteome Res 2010; 9:1541-8. [PMID: 20095645 DOI: 10.1021/pr901043e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
APPL1 is a membrane-associated adaptor protein implicated in various cellular processes, including apoptosis, proliferation, and survival. Although there is increasing interest in the biological roles as well as the protein and membrane interactions of APPL1, a comprehensive phosphorylation profile has not been generated. In this study, we use mass spectrometry (MS) to identify 13 phosphorylated residues within APPL1. By using multiple proteases (trypsin, chymotrypsin, and Glu C) and replicate experiments of linear ion trap (LTQ) MS and LTQ-Orbitrap-MS, a combined sequence coverage of 99.6% is achieved. Four of the identified sites are located in important functional domains, suggesting a potential role in regulating APPL1. One of these sites is within the BAR domain, two cluster near the edge of the PH domain, and one is located within the PTB domain. These phosphorylation sites may control APPL1 function by regulating the ability of APPL1 domains to interact with other proteins and membranes.
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Affiliation(s)
- Randi L Gant-Branum
- Department of Chemistry, Vanderbilt Institute for Chemical Biology (VICB), Vanderbilt University, Nashville, Tennessee 37235, USA
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44
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Bae GU, Lee JR, Kim BG, Han JW, Leem YE, Lee HJ, Ho SM, Hahn MJ, Kang JS. Cdo interacts with APPL1 and activates Akt in myoblast differentiation. Mol Biol Cell 2010; 21:2399-411. [PMID: 20484574 PMCID: PMC2903669 DOI: 10.1091/mbc.e09-12-1011] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Cdo activates Akt via indirect interaction with APPL1 during myoblast differentiation, and this complex likely mediates some of the promyogenic effect of cell–cell interaction. The promyogenic function of Cdo involves a coordinated activation of p38MAPK and Akt via interaction with scaffold proteins, JLP and Bnip-2 for p38MAPK and APPL1 for Akt. Cell–cell interactions between muscle precursors are required for myogenic differentiation; however, underlying mechanisms are largely unknown. Promyogenic cell surface protein Cdo functions as a component of multiprotein complexes containing other cell adhesion molecules, Boc, Neogenin and N-cadherin, and mediates some of signals triggered by cell–cell interactions between muscle precursors. Cdo activates p38MAPK via interaction with two scaffold proteins JLP and Bnip-2 to promote myogenesis. p38MAPK and Akt signaling are required for myogenic differentiation and activation of both signaling pathways is crucial for efficient myogenic differentiation. We report here that APPL1, an interacting partner of Akt, forms complexes with Cdo and Boc in differentiating myoblasts. Both Cdo and APPL1 are required for efficient Akt activation during myoblast differentiation. The defective differentiation of Cdo-depleted cells is fully rescued by overexpression of a constitutively active form of Akt, whereas overexpression of APPL1 fails to do so. Taken together, Cdo activates Akt through association with APPL1 during myoblast differentiation, and this complex likely mediates some of the promyogenic effect of cell–cell interaction. The promyogenic function of Cdo involves a coordinated activation of p38MAPK and Akt via association with scaffold proteins, JLP and Bnip-2 for p38MAPK and APPL1 for Akt.
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Affiliation(s)
- Gyu-Un Bae
- Department of Molecular Cell Biology, Center for Molecular Medicine, Samsung Biomedical Research Institute, Sungkyunkwan University School of Medicine, Suwon 440-746, Republic of Korea
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45
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Tan Y, You H, Wu C, Altomare DA, Testa JR. Appl1 is dispensable for mouse development, and loss of Appl1 has growth factor-selective effects on Akt signaling in murine embryonic fibroblasts. J Biol Chem 2009; 285:6377-89. [PMID: 20040596 DOI: 10.1074/jbc.m109.068452] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The adaptor protein APPL1 (adaptor protein containing pleckstrin homology (PH), phosphotyrosine binding (PTB), and leucine zipper motifs) was first identified as a binding protein of AKT2 by yeast two-hybrid screening. APPL1 was subsequently found to bind to several membrane-bound receptors and was implicated in their signal transduction through AKT and/or MAPK pathways. To determine the unambiguous role of Appl1 in vivo, we generated Appl1 knock-out mice. Here we report that Appl1 knock-out mice are viable and fertile. Appl1-null mice were born at expected Mendelian ratios, without obvious phenotypic abnormalities. Moreover, Akt activity in various fetal tissues was unchanged compared with that observed in wild-type littermates. Studies of isolated Appl1(-/-) murine embryonic fibroblasts (MEFs) showed that Akt activation by epidermal growth factor, insulin, or fetal bovine serum was similar to that observed in wild-type MEFs, although Akt activation by HGF was diminished in Appl1(-/-) MEFs. To rule out a possible redundant role played by the related Appl2, we used small interfering RNA to knock down Appl2 expression in Appl1(-/-) MEFs. Unexpectedly, cell survival was unaffected under normal culture conditions, and activation of Akt was unaltered following epidermal growth factor stimulation, although Akt activity did decrease further after HGF stimulation. Furthermore, we found that Appl proteins are required for HGF-induced cell survival and migration via activation of Akt. Our studies suggest that Appl1 is dispensable for development and only participate in Akt signaling under certain conditions.
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Affiliation(s)
- Yinfei Tan
- Cancer Genetics and Signaling Program, Fox Chase Cancer Center, Philadelphia, Pennsylvania 19111, USA
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46
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Shibata Y, Hu J, Kozlov MM, Rapoport TA. Mechanisms Shaping the Membranes of Cellular Organelles. Annu Rev Cell Dev Biol 2009; 25:329-54. [DOI: 10.1146/annurev.cellbio.042308.113324] [Citation(s) in RCA: 328] [Impact Index Per Article: 21.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Yoko Shibata
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115; ,
| | - Junjie Hu
- College of Life Sciences, Nankai University, 300071 Tianjin, China;
| | - Michael M. Kozlov
- Department of Physiology and Pharmacology, Sackler Faculty of Medicine, Tel Aviv University, 69978 Tel Aviv, Israel;
| | - Tom A. Rapoport
- Howard Hughes Medical Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115; ,
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47
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Rashid S, Pilecka I, Torun A, Olchowik M, Bielinska B, Miaczynska M. Endosomal adaptor proteins APPL1 and APPL2 are novel activators of beta-catenin/TCF-mediated transcription. J Biol Chem 2009; 284:18115-28. [PMID: 19433865 PMCID: PMC2709337 DOI: 10.1074/jbc.m109.007237] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2009] [Revised: 05/06/2009] [Indexed: 12/22/2022] Open
Abstract
Canonical Wnt signaling regulates many aspects of cellular physiology and tissue homeostasis during development and in adult organisms. In molecular terms, stimulation by Wnt ligands leads to the stabilization of beta-catenin, its translocation to the nucleus, and stimulation of TCF (T-cell factor)-dependent transcription of target genes. This process is controlled at various stages by a number of regulatory proteins, including transcriptional activators and repressors. Here we demonstrate that the endosomal proteins APPL1 and APPL2 are novel activators of beta-catenin/TCF-mediated transcription. APPL proteins are multifunctional adaptors and effectors of the small GTPase Rab5, which localize to a subpopulation of early endosomes but are also capable of nucleocytoplasmic shuttling. Overexpression of APPL1 or APPL2 protein stimulates the activity of beta-catenin/TCF-dependent reporter construct, whereas silencing of APPL1 reduces it. Both APPL proteins interact directly with Reptin, a transcriptional repressor binding to beta-catenin and HDAC1 (histone deacetylase 1), and this interaction was mapped to the pleckstrin homology domain of APPL1. Moreover, APPL proteins are present in an endogenous complex containing Reptin, beta-catenin, HDAC1, and HDAC2. Overexpression of either APPL protein relieves Reptin-dependent transcriptional repression and correlates with the reduced amounts of HDACs and beta-catenin associated with Reptin as well as with the lower levels of Reptin and HDAC1 on the promoters of beta-catenin target genes. We propose that APPL proteins exert their stimulatory effects on beta-catenin/TCF-dependent transcription by decreasing the activity of a Reptin-containing repressive complex.
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Affiliation(s)
- Sajid Rashid
- From the Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Iwona Pilecka
- From the Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Anna Torun
- From the Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Marta Olchowik
- From the Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Beata Bielinska
- From the Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland
| | - Marta Miaczynska
- From the Laboratory of Cell Biology, International Institute of Molecular and Cell Biology, Ks. Trojdena 4, 02-109 Warsaw, Poland
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48
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Cheng KKY, Iglesias MA, Lam KSL, Wang Y, Sweeney G, Zhu W, Vanhoutte PM, Kraegen EW, Xu A. APPL1 potentiates insulin-mediated inhibition of hepatic glucose production and alleviates diabetes via Akt activation in mice. Cell Metab 2009; 9:417-27. [PMID: 19416712 DOI: 10.1016/j.cmet.2009.03.013] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2008] [Revised: 02/06/2009] [Accepted: 03/31/2009] [Indexed: 10/20/2022]
Abstract
Hepatic insulin resistance is the major contributor to fasting hyperglycemia in type 2 diabetes. Here we report that the endosomal adaptor protein APPL1 increases hepatic insulin sensitivity by potentiating insulin-mediated suppression of the gluconeogenic program. Insulin-stimulated activation of Akt and suppression of gluconeogenesis in hepatocytes are enhanced by APPL1 overexpression, but are attenuated by APPL1 knockdown. APPL1 interacts with Akt and blocks the association of Akt with its endogenous inhibitor tribble 3 (TRB3) through direct competition, thereby promoting Akt translocation to the plasma membrane and the endosomes for further activation. In db/db diabetic mice, the blockage of the augmented interaction between Akt and TRB3 by hepatic overexpression of APPL1 is accompanied by a marked attenuation of hyperglycemia and insulin resistance. These results suggest that the potentiating effects of APPL1 on insulin-stimulated suppression of hepatic glucose production are attributed to its ability in counteracting the inhibition of Akt activation by TRB3.
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49
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Zoncu R, Perera RM, Balkin DM, Pirruccello M, Toomre D, De Camilli P. A phosphoinositide switch controls the maturation and signaling properties of APPL endosomes. Cell 2009; 136:1110-21. [PMID: 19303853 DOI: 10.1016/j.cell.2009.01.032] [Citation(s) in RCA: 271] [Impact Index Per Article: 18.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2008] [Revised: 11/12/2008] [Accepted: 01/06/2009] [Indexed: 01/11/2023]
Abstract
The recent identification of several novel endocytic compartments has challenged our current understanding of the topological and functional organization of the endocytic pathway. Using quantitative single vesicle imaging and acute manipulation of phosphoinositides we show that APPL endosomes, which participate in growth factor receptor trafficking and signaling, represent an early endocytic intermediate common to a subset of clathrin derived endocytic vesicles and macropinosomes. Most APPL endosomes are precursors of classical PI3P positive endosomes, and PI3P plays a critical role in promoting this conversion. Depletion of PI3P causes a striking reversion of Rab5 positive endosomes to the APPL stage, and results in enhanced growth factor signaling. These findings reveal a surprising plasticity of the early endocytic pathway. Importantly, PI3P functions as a switch to dynamically regulate maturation and signaling of APPL endosomes.
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Affiliation(s)
- Roberto Zoncu
- Department of Cell Biology, Kavli Institute for Neuroscience and Program in Cellular Neuroscience, Neurodegeneration and Repair, Yale University School of Medicine, New Haven, CT 06510, USA
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50
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Saarikangas J, Zhao H, Pykäläinen A, Laurinmäki P, Mattila PK, Kinnunen PKJ, Butcher SJ, Lappalainen P. Molecular mechanisms of membrane deformation by I-BAR domain proteins. Curr Biol 2009; 19:95-107. [PMID: 19150238 DOI: 10.1016/j.cub.2008.12.029] [Citation(s) in RCA: 232] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2008] [Revised: 11/26/2008] [Accepted: 12/08/2008] [Indexed: 02/06/2023]
Abstract
BACKGROUND Generation of membrane curvature is critical for the formation of plasma membrane protrusions and invaginations and for shaping intracellular organelles. Among the central regulators of membrane dynamics are the BAR superfamily domains, which deform membranes into tubular structures. In contrast to the relatively well characterized BAR and F-BAR domains that promote the formation of plasma membrane invaginations, I-BAR domains induce plasma membrane protrusions through a poorly understood mechanism. RESULTS We show that I-BAR domains induce strong PI(4,5)P(2) clustering upon membrane binding, bend the membrane through electrostatic interactions, and remain dynamically associated with the inner leaflet of membrane tubules. Thus, I-BAR domains induce the formation of dynamic membrane protrusions to the opposite direction than do BAR and F-BAR domains. Strikingly, comparison of different I-BAR domains revealed that they deform PI(4,5)P(2)-rich membranes through distinct mechanisms. IRSp53 and IRTKS I-BARs bind membranes mainly through electrostatic interactions, whereas MIM and ABBA I-BARs additionally insert an amphipathic helix into the membrane bilayer, resulting in larger tubule diameter in vitro and more efficient filopodia formation in vivo. Furthermore, FRAP analysis revealed that whereas the mammalian I-BAR domains display dynamic association with filopodia, the C. elegans I-BAR domain forms relatively stable structures inside the plasma membrane protrusions. CONCLUSIONS These data define I-BAR domain as a functional member of the BAR domain superfamily and unravel the mechanisms by which I-BAR domains deform membranes to induce filopodia in cells. Furthermore, our work reveals unexpected divergence in the mechanisms by which evolutionarily distinct groups of I-BAR domains interact with PI(4,5)P(2)-rich membranes.
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Affiliation(s)
- Juha Saarikangas
- Program in Cell and Molecular Biology, Institute of Biotechnology, P.O. Box 56, University of Helsinki, FIN-00014 Helsinki, Finland
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