1
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Glading A. KRIT1 in vascular biology and beyond. Biosci Rep 2024; 44:BSR20231675. [PMID: 38980708 PMCID: PMC11263069 DOI: 10.1042/bsr20231675] [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: 02/10/2024] [Revised: 06/21/2024] [Accepted: 07/09/2024] [Indexed: 07/10/2024] Open
Abstract
KRIT1 is a 75 kDa scaffolding protein which regulates endothelial cell phenotype by limiting the response to inflammatory stimuli and maintaining a quiescent and stable endothelial barrier. Loss-of-function mutations in KRIT1 lead to the development of cerebral cavernous malformations (CCM), a disease marked by the formation of abnormal blood vessels which exhibit a loss of barrier function, increased endothelial proliferation, and altered gene expression. While many advances have been made in our understanding of how KRIT1, and the functionally related proteins CCM2 and PDCD10, contribute to the regulation of blood vessels and the vascular barrier, some important open questions remain. In addition, KRIT1 is widely expressed and KRIT1 and the other CCM proteins have been shown to play important roles in non-endothelial cell types and tissues, which may or may not be related to their role as pathogenic originators of CCM. In this review, we discuss some of the unsettled questions regarding the role of KRIT1 in vascular physiology and discuss recent advances that suggest this ubiquitously expressed protein may have a role beyond the endothelial cell.
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Affiliation(s)
- Angela J. Glading
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, U.S.A
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2
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Singla A, Boesch DJ, Joyce Fung HY, Ngoka C, Enriquez AS, Song R, Kramer DA, Han Y, Juneja P, Billadeau DD, Bai X, Chen Z, Turer EE, Burstein E, Chen B. Structural basis for Retriever-SNX17 assembly and endosomal sorting. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.12.584676. [PMID: 38559023 PMCID: PMC10980035 DOI: 10.1101/2024.03.12.584676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
During endosomal recycling, Sorting Nexin 17 (SNX17) facilitates the transport of numerous membrane cargo proteins by tethering them to the Retriever complex. Despite its importance, the mechanisms underlying this interaction have remained elusive. Here, we report the structure of the Retriever-SNX17 complex determined using cryogenic electron microscopy (cryo-EM). Our structure reveals that the C-terminal tail of SNX17 engages with a highly conserved interface between the VPS35L and VPS26C subunits of Retriever. Through comprehensive biochemical, cellular, and proteomic analyses, we demonstrate that disrupting this interface impairs the Retriever-SNX17 interaction, subsequently affecting the recycling of SNX17-dependent cargos and altering the composition of the plasma membrane proteome. Intriguingly, we find that the SNX17-binding pocket on Retriever can be utilized by other ligands that share a consensus acidic C-terminal tail motif. By showing how SNX17 is linked to Retriever, our findings uncover a fundamental mechanism underlying endosomal trafficking of critical cargo proteins and reveal a mechanism by which Retriever can engage with other regulatory factors.
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Affiliation(s)
- Amika Singla
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Daniel J. Boesch
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Ho Yee Joyce Fung
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Chigozie Ngoka
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Avery S. Enriquez
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Ran Song
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Daniel A. Kramer
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Yan Han
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Puneet Juneja
- Cryo-EM facility, Office of Biotechnology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
| | - Daniel D. Billadeau
- Division of Oncology Research, College of Medicine, Mayo Clinic, Rochester MN, 55905, USA
| | - Xiaochen Bai
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Zhe Chen
- Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
| | - Emre E. Turer
- Center for the Genetics of Host Defense, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Ezra Burstein
- Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
- Department of Molecular Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390, USA
| | - Baoyu Chen
- Roy J. Carver Department of Biochemistry, Biophysics & Molecular Biology, Iowa State University, 2437 Pammel Drive, Ames, IA 50011, USA
- On sabbatical leave at Department of Biophysics, University of Texas Southwestern Medical Center, 6001 Forest Park Road, Dallas, TX 75390, USA
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3
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Cui Q, Liang S, Li H, Guo Y, Lv J, Wang X, Qin P, Xu H, Huang TY, Lu Y, Tian Q, Zhang T. SNX17 Mediates Dendritic Spine Maturation via p140Cap. Mol Neurobiol 2024; 61:1346-1362. [PMID: 37704928 DOI: 10.1007/s12035-023-03620-4] [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: 01/11/2023] [Accepted: 08/24/2023] [Indexed: 09/15/2023]
Abstract
Sorting nexin17 (SNX17) is a member of the sorting nexin family, which plays a crucial role in endosomal trafficking. Previous research has shown that SNX17 is involved in the recycling or degradation of various proteins associated with neurodevelopmental and neurological diseases in cell models. However, the significance of SNX17 in neurological function in the mouse brain has not been thoroughly investigated. In this study, we generated Snx17 knockout mice and observed that the homozygous deletion of Snx17 (Snx17-/-) resulted in lethality. On the other hand, heterozygous mutant mice (Snx17+/-) exhibited anxiety-like behavior with a reduced preference for social novelty. Furthermore, Snx17 haploinsufficiency led to impaired synaptic transmission and reduced maturation of dendritic spines. Through GST pulldown and interactome analysis, we identified the SRC kinase inhibitor, p140Cap, as a potential downstream target of SNX17. We also demonstrated that the interaction between p140Cap and SNX17 is crucial for dendritic spine maturation. Together, this study provides the first in vivo evidence highlighting the important role of SNX17 in maintaining neuronal function, as well as regulating social novelty and anxiety-like behaviors.
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Affiliation(s)
- Qiuyan Cui
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Shiqi Liang
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Hao Li
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Yiqing Guo
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Junkai Lv
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Xinyuan Wang
- Department of Pediatrics, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Chongqing, 400016, China
| | - Pengwei Qin
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Huaxi Xu
- Institute for Brain Science and Disease, Chongqing Medical University, Chongqing, 400016, China
| | - Timothy Y Huang
- Degenerative Diseases Program, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, 92037, USA
| | - Youming Lu
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Qing Tian
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Department of Pathophysiology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
| | - Tongmei Zhang
- The Institute for Brain Research, Collaborative Innovation Center for Brain Science, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Department of Histology and Embryology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
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4
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Swamy H, Glading AJ. Is Location Everything? Regulation of the Endothelial CCM Signaling Complex. Front Cardiovasc Med 2022; 9:954780. [PMID: 35898265 PMCID: PMC9309484 DOI: 10.3389/fcvm.2022.954780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2022] [Accepted: 06/17/2022] [Indexed: 11/13/2022] Open
Abstract
Recent advances have steadily increased the number of proteins and pathways known to be involved in the development of cerebral cavernous malformation (CCM). Our ability to synthesize this information into a cohesive and accurate signaling model is limited, however, by significant gaps in our knowledge of how the core CCM proteins, whose loss of function drives development of CCM, are regulated. Here, we review what is known about the regulation of the three core CCM proteins, the scaffolds KRIT1, CCM2, and CCM3, with an emphasis on binding interactions and subcellular location, which frequently control scaffolding protein function. We highlight recent work that challenges the current model of CCM complex signaling and provide recommendations for future studies needed to address the large number of outstanding questions.
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Affiliation(s)
- Harsha Swamy
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, United States
| | - Angela J Glading
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, United States
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5
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Vieira N, Rito T, Correia-Neves M, Sousa N. Sorting Out Sorting Nexins Functions in the Nervous System in Health and Disease. Mol Neurobiol 2021; 58:4070-4106. [PMID: 33931804 PMCID: PMC8280035 DOI: 10.1007/s12035-021-02388-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/05/2021] [Indexed: 12/18/2022]
Abstract
Endocytosis is a fundamental process that controls protein/lipid composition of the plasma membrane, thereby shaping cellular metabolism, sensing, adhesion, signaling, and nutrient uptake. Endocytosis is essential for the cell to adapt to its surrounding environment, and a tight regulation of the endocytic mechanisms is required to maintain cell function and survival. This is particularly significant in the central nervous system (CNS), where composition of neuronal cell surface is crucial for synaptic functioning. In fact, distinct pathologies of the CNS are tightly linked to abnormal endolysosomal function, and several genome wide association analysis (GWAS) and biochemical studies have identified intracellular trafficking regulators as genetic risk factors for such pathologies. The sorting nexins (SNXs) are a family of proteins involved in protein trafficking regulation and signaling. SNXs dysregulation occurs in patients with Alzheimer’s disease (AD), Down’s syndrome (DS), schizophrenia, ataxia and epilepsy, among others, establishing clear roles for this protein family in pathology. Interestingly, restoration of SNXs levels has been shown to trigger synaptic plasticity recovery in a DS mouse model. This review encompasses an historical and evolutionary overview of SNXs protein family, focusing on its organization, phyla conservation, and evolution throughout the development of the nervous system during speciation. We will also survey SNXs molecular interactions and highlight how defects on SNXs underlie distinct pathologies of the CNS. Ultimately, we discuss possible strategies of intervention, surveying how our knowledge about the fundamental processes regulated by SNXs can be applied to the identification of novel therapeutic avenues for SNXs-related disorders.
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Affiliation(s)
- Neide Vieira
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal. .,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal.
| | - Teresa Rito
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Margarida Correia-Neves
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
| | - Nuno Sousa
- Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, Campus Gualtar, 4710-057, Braga, Portugal.,ICVS/3B's - PT Government Associate Laboratory, Braga/Guimarães, Portugal
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6
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Riolo G, Ricci C, Battistini S. Molecular Genetic Features of Cerebral Cavernous Malformations (CCM) Patients: An Overall View from Genes to Endothelial Cells. Cells 2021; 10:704. [PMID: 33810005 PMCID: PMC8005105 DOI: 10.3390/cells10030704] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Revised: 03/18/2021] [Accepted: 03/18/2021] [Indexed: 02/07/2023] Open
Abstract
Cerebral cavernous malformations (CCMs) are vascular lesions that affect predominantly microvasculature in the brain and spinal cord. CCM can occur either in sporadic or familial form, characterized by autosomal dominant inheritance and development of multiple lesions throughout the patient's life. Three genes associated with CCM are known: CCM1/KRIT1 (krev interaction trapped 1), CCM2/MGC4607 (encoding a protein named malcavernin), and CCM3/PDCD10 (programmed cell death 10). All the mutations identified in these genes cause a loss of function and compromise the protein functions needed for maintaining the vascular barrier integrity. Loss of function of CCM proteins causes molecular disorganization and dysfunction of endothelial adherens junctions. In this review, we provide an overall vision of the CCM pathology, starting with the genetic bases of the disease, describing the role of the proteins, until we reach the cellular level. Thus, we summarize the genetics of CCM, providing a description of CCM genes and mutation features, provided an updated knowledge of the CCM protein structure and function, and discuss the molecular mechanisms through which CCM proteins may act within endothelial cells, particularly in endothelial barrier maintenance/regulation and in cellular signaling.
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Affiliation(s)
| | | | - Stefania Battistini
- Department of Medical, Surgical and Neurological Sciences, University of Siena, 53100 Siena, Italy; (G.R.); (C.R.)
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7
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De Luca E, Perrelli A, Swamy H, Nitti M, Passalacqua M, Furfaro AL, Salzano AM, Scaloni A, Glading AJ, Retta SF. Protein kinase Cα regulates the nucleocytoplasmic shuttling of KRIT1. J Cell Sci 2021; 134:jcs250217. [PMID: 33443102 PMCID: PMC7875496 DOI: 10.1242/jcs.250217] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 12/15/2020] [Indexed: 12/16/2022] Open
Abstract
KRIT1 is a scaffolding protein that regulates multiple molecular mechanisms, including cell-cell and cell-matrix adhesion, and redox homeostasis and signaling. However, rather little is known about how KRIT1 is itself regulated. KRIT1 is found in both the cytoplasm and the nucleus, yet the upstream signaling proteins and mechanisms that regulate KRIT1 nucleocytoplasmic shuttling are not well understood. Here, we identify a key role for protein kinase C (PKC) in this process. In particular, we found that PKC activation promotes the redox-dependent cytoplasmic localization of KRIT1, whereas inhibition of PKC or treatment with the antioxidant N-acetylcysteine leads to KRIT1 nuclear accumulation. Moreover, we demonstrated that the N-terminal region of KRIT1 is crucial for the ability of PKC to regulate KRIT1 nucleocytoplasmic shuttling, and may be a target for PKC-dependent regulatory phosphorylation events. Finally, we found that silencing of PKCα, but not PKCδ, inhibits phorbol 12-myristate 13-acetate (PMA)-induced cytoplasmic enrichment of KRIT1, suggesting a major role for PKCα in regulating KRIT1 nucleocytoplasmic shuttling. Overall, our findings identify PKCα as a novel regulator of KRIT1 subcellular compartmentalization, thus shedding new light on the physiopathological functions of this protein.
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Affiliation(s)
- Elisa De Luca
- Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
- CCM Italia Research Network, National Coordination Center at the Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
- Center for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia, 73010 Arnesano, Lecce, Italy
| | - Andrea Perrelli
- Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
- CCM Italia Research Network, National Coordination Center at the Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
| | - Harsha Swamy
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Mariapaola Nitti
- Department of Experimental Medicine, University of Genoa, 16132 Genova, Italy
| | - Mario Passalacqua
- Department of Experimental Medicine, University of Genoa, 16132 Genova, Italy
| | - Anna Lisa Furfaro
- Department of Experimental Medicine, University of Genoa, 16132 Genova, Italy
| | - Anna Maria Salzano
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, 80147 Napoli, Italy
| | - Andrea Scaloni
- Proteomics & Mass Spectrometry Laboratory, ISPAAM, National Research Council, 80147 Napoli, Italy
| | - Angela J Glading
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY 14642, USA
| | - Saverio Francesco Retta
- Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
- CCM Italia Research Network, National Coordination Center at the Department of Clinical and Biological Sciences, University of Torino, 10043 Orbassano, Torino, Italy
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8
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Zhang P, Azizi L, Kukkurainen S, Gao T, Baikoghli M, Jacquier MC, Sun Y, Määttä JAE, Cheng RH, Wehrle-Haller B, Hytönen VP, Wu J. Crystal structure of the FERM-folded talin head reveals the determinants for integrin binding. Proc Natl Acad Sci U S A 2020; 117:32402-32412. [PMID: 33288722 PMCID: PMC7768682 DOI: 10.1073/pnas.2014583117] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Binding of the intracellular adapter proteins talin and its cofactor, kindlin, to the integrin receptors induces integrin activation and clustering. These processes are essential for cell adhesion, migration, and organ development. Although the talin head, the integrin-binding segment in talin, possesses a typical FERM-domain sequence, a truncated form has been crystallized in an unexpected, elongated form. This form, however, lacks a C-terminal fragment and possesses reduced β3-integrin binding. Here, we present a crystal structure of a full-length talin head in complex with the β3-integrin tail. The structure reveals a compact FERM-like conformation and a tightly associated N-P-L-Y motif of β3-integrin. A critical C-terminal poly-lysine motif mediates FERM interdomain contacts and assures the tight association with the β3-integrin cytoplasmic segment. Removal of the poly-lysine motif or disrupting the FERM-folded configuration of the talin head significantly impairs integrin activation and clustering. Therefore, structural characterization of the FERM-folded active talin head provides fundamental understanding of the regulatory mechanism of integrin function.
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Affiliation(s)
- Pingfeng Zhang
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Latifeh Azizi
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland
- Department of Clinical Chemistry, Fimlab Laboratories, FI-33520 Tampere, Finland
| | - Sampo Kukkurainen
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland
- Department of Clinical Chemistry, Fimlab Laboratories, FI-33520 Tampere, Finland
| | - Tong Gao
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Mo Baikoghli
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Marie-Claude Jacquier
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, 1211 Geneva 4, Switzerland
| | - Yijuan Sun
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111
| | - Juha A E Määttä
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland
- Department of Clinical Chemistry, Fimlab Laboratories, FI-33520 Tampere, Finland
| | - R Holland Cheng
- Department of Molecular and Cellular Biology, University of California, Davis, CA 95616
| | - Bernhard Wehrle-Haller
- Department of Cell Physiology and Metabolism, Centre Médical Universitaire, University of Geneva, 1211 Geneva 4, Switzerland
| | - Vesa P Hytönen
- Faculty of Medicine and Health Technology, Tampere University, FI-33520 Tampere, Finland;
- Department of Clinical Chemistry, Fimlab Laboratories, FI-33520 Tampere, Finland
| | - Jinhua Wu
- Molecular Therapeutics Program, Fox Chase Cancer Center, Philadelphia, PA 19111;
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9
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Abstract
Cerebral cavernous malformations (CCMs) are neurovascular abnormalities characterized by thin, leaky blood vessels resulting in lesions that predispose to haemorrhages, stroke, epilepsy and focal neurological deficits. CCMs arise due to loss-of-function mutations in genes encoding one of three CCM complex proteins, KRIT1, CCM2 or CCM3. These widely expressed, multi-functional adaptor proteins can assemble into a CCM protein complex and (either alone or in complex) modulate signalling pathways that influence cell adhesion, cell contractility, cytoskeletal reorganization and gene expression. Recent advances, including analysis of the structures and interactions of CCM proteins, have allowed substantial progress towards understanding the molecular bases for CCM protein function and how their disruption leads to disease. Here, we review current knowledge of CCM protein signalling with a focus on three pathways which have generated the most interest—the RhoA–ROCK, MEKK3–MEK5–ERK5–KLF2/4 and cell junctional signalling pathways—but also consider ICAP1-β1 integrin and cdc42 signalling. We discuss emerging links between these pathways and the processes that drive disease pathology and highlight important open questions—key among them is the role of subcellular localization in the control of CCM protein activity.
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Affiliation(s)
- Valerie L Su
- Department of Pharmacology, Yale University School of Medicine, PO Box 208066, 333 Cedar Street, New Haven, CT 06520, USA
| | - David A Calderwood
- Department of Pharmacology, Yale University School of Medicine, PO Box 208066, 333 Cedar Street, New Haven, CT 06520, USA.,Department of Cell Biology, Yale University School of Medicine, PO Box 208066, 333 Cedar Street, New Haven, CT 06520, USA
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10
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da Fontoura Galvão G, Veloso da Silva E, Fontes-Dantas FL, Filho RC, Alves-Leon S, Marcondes de Souza J. First Report of Concomitant Pathogenic Mutations Within MGC4607/CCM2 and KRIT1/CCM1 in a Familial Cerebral Cavernous Malformation Patient. World Neurosurg 2020; 142:481-486.e1. [DOI: 10.1016/j.wneu.2020.06.170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 06/18/2020] [Accepted: 06/21/2020] [Indexed: 10/24/2022]
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11
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Martinelli L, Adamopoulos A, Johansson P, Wan PT, Gunnarsson J, Guo H, Boyd H, Zelcer N, Sixma TK. Structural analysis of the LDL receptor-interacting FERM domain in the E3 ubiquitin ligase IDOL reveals an obscured substrate-binding site. J Biol Chem 2020; 295:13570-13583. [PMID: 32727844 PMCID: PMC7521653 DOI: 10.1074/jbc.ra120.014349] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Revised: 07/21/2020] [Indexed: 12/31/2022] Open
Abstract
Hepatic abundance of the low-density lipoprotein receptor (LDLR) is a critical determinant of circulating plasma LDL cholesterol levels and hence development of coronary artery disease. The sterol-responsive E3 ubiquitin ligase inducible degrader of the LDLR (IDOL) specifically promotes ubiquitination and subsequent lysosomal degradation of the LDLR and thus controls cellular LDL uptake. IDOL contains an extended N-terminal FERM (4.1 protein, ezrin, radixin, and moesin) domain, responsible for substrate recognition and plasma membrane association, and a second C-terminal RING domain, responsible for the E3 ligase activity and homodimerization. As IDOL is a putative lipid-lowering drug target, we investigated the molecular details of its substrate recognition. We produced and isolated full-length IDOL protein, which displayed high autoubiquitination activity. However, in vitro ubiquitination of its substrate, the intracellular tail of the LDLR, was low. To investigate the structural basis for this, we determined crystal structures of the extended FERM domain of IDOL and multiple conformations of its F3ab subdomain. These reveal the archetypal F1-F2-F3 trilobed FERM domain structure but show that the F3c subdomain orientation obscures the target-binding site. To substantiate this finding, we analyzed the full-length FERM domain and a series of truncated FERM constructs by small-angle X-ray scattering (SAXS). The scattering data support a compact and globular core FERM domain with a more flexible and extended C-terminal region. This flexibility may explain the low activity in vitro and suggests that IDOL may require activation for recognition of the LDLR.
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Affiliation(s)
- Luca Martinelli
- Division of Biochemistry, Netherlands Cancer Institute, Amsterdam, The Netherlands; Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Amsterdam, the Netherlands
| | | | - Patrik Johansson
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Paul T Wan
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Jenny Gunnarsson
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Hongwei Guo
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Helen Boyd
- IMED Biotech Unit, Discovery Sciences, AstraZeneca, Mölndal, Sweden
| | - Noam Zelcer
- Department of Medical Biochemistry, Amsterdam UMC, Amsterdam Cardiovascular Sciences and Gastroenterology and Metabolism, University of Amsterdam, Amsterdam, the Netherlands.
| | - Titia K Sixma
- Division of Biochemistry, Netherlands Cancer Institute, Amsterdam, The Netherlands; Oncode Institute, Utrecht, The Netherlands.
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12
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Fisher OS, Li X, Liu W, Zhang R, Boggon TJ. Crystallographic Studies of the Cerebral Cavernous Malformations Proteins. Methods Mol Biol 2020; 2152:291-302. [PMID: 32524560 DOI: 10.1007/978-1-0716-0640-7_21] [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] [Indexed: 12/13/2022]
Abstract
Cerebral cavernous malformations (CCM) are dysplasias that primarily occur in the neurovasculature, and are associated with mutations in three genes: KRIT1, CCM2, and PDCD10, the protein products of which are KRIT1 (Krev/Rap1 Interaction Trapped 1; CCM1, cerebral cavernous malformations 1), CCM2 (cerebral cavernous malformations 2; OSM, osmosensing scaffold for MEKK3), and CCM3 (cerebral cavernous malformations 3; PDCD10, programmed cell death 10). Until recently, these proteins were relatively understudied at the molecular level, and only three folded domains were documented. These were a band 4.1, ezrin, radixin, moesin (FERM), and an ankyrin repeat domain (ARD) in KRIT1, and a phosphotyrosine-binding (PTB) domain in CCM2. Over the past 10 years, a crystallographic approach has been used to discover a series of previously unidentified domains within the CCM proteins. These include a non-functional Nudix (or pseudonudix) domain in KRIT1, a harmonin homology domain (HHD) in CCM2, and dimerization and focal adhesion targeting (FAT)-homology domains within CCM3. Many of the roles of these domains have been revealed by structure-guided studies that show the CCM proteins can directly interact with one another to form a signaling scaffold, and that the "CCM complex" functions in signal transduction by interacting with other binding partners, including ICAP1, RAP1, and MEKK3. In this chapter, we describe the crystallization of CCM protein domains alone, and with their interaction partners.
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Affiliation(s)
- Oriana S Fisher
- Department of Pharmacology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT, USA.,Department of Chemistry, Lehigh University, Bethlehem, PA, USA
| | - Xiaofeng Li
- Department of Pharmacology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT, USA.,Abcam Inc., Branford, CT, USA
| | - Weizhi Liu
- Department of Pharmacology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT, USA.,MOE Key Laboratory of Marine Genetics and Breeding, College of Marine Life Sciences, Ocean University of China, Qingdao, China.,Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
| | - Rong Zhang
- Department of Pharmacology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT, USA
| | - Titus J Boggon
- Department of Pharmacology, Yale Cancer Center, Yale University School of Medicine, New Haven, CT, USA. .,Department of Molecular Biophysics and Biochemistry, Yale Cancer Center, Yale University School of Medicine, New Haven, CT, USA.
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13
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Abstract
Cerebral cavernous malformations (CCM) are manifested by microvascular lesions characterized by leaky endothelial cells with minimal intervening parenchyma predominantly in the central nervous system predisposed to hemorrhagic stroke, resulting in focal neurological defects. Till date, three proteins are implicated in this condition: CCM1 (KRIT1), CCM2 (MGC4607), and CCM3 (PDCD10). These multi-domain proteins form a protein complex via CCM2 that function as a docking site for the CCM signaling complex, which modulates many signaling pathways. Defects in the formation of this signaling complex have been shown to affect a wide range of cellular processes including cell-cell contact stability, vascular angiogenesis, oxidative damage protection and multiple biogenic events. In this review we provide an update on recent advances in structure and function of these CCM proteins, especially focusing on the signaling cascades involved in CCM pathogenesis and the resultant CCM cellular phenotypes in the past decade.
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Affiliation(s)
- Akhil Padarti
- Department of Biomedical Sciences, Texas Tech University Health Science Center El Paso, El Paso, TX 79905, USA
| | - Jun Zhang
- Department of Biomedical Sciences, Texas Tech University Health Science Center El Paso, El Paso, TX 79905, USA
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14
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Zhao D, Li X, Liang H, Zheng N, Pan Z, Zhou Y, Liu X, Qian M, Xu B, Zhang Y, Feng Y, Qili M, Wu Q, Yang B, Shan H. SNX17 produces anti-arrhythmic effects by preserving functional SERCA2a protein in myocardial infarction. Int J Cardiol 2018; 272:298-305. [PMID: 30025651 DOI: 10.1016/j.ijcard.2018.07.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/19/2018] [Accepted: 07/03/2018] [Indexed: 11/26/2022]
Abstract
BACKGROUND Sorting nexin 17 (SNX17) is a critical cytoplasmic adaptor protein that regulates endosomal trafficking of membrane proteins to determine their recycling and/or degradation. The potential role of SNX17 in cardiovascular pathophysiology has not been reported. METHODS AND RESULTS Cardiac arrhythmias were monitored using standard limb lead II electrocardiograph, and cardiac performances were determined by echocardiography in a rat model of myocardial infarction (MI) created by left anterior descending coronary artery ligation. We found that SNX17 was substantially downregulated in ischemic myocardium. The downregulation contributed to the cardiac electrical disturbances and contractile dysfunction as SNX17 replacement mitigated the detrimental alterations of MI hearts. Specifically, silence of SNX17 expression using RNA interference caused intracellular Ca2+ overload as revealed by the abnormal rise of resting [Ca2+]i and deceleration of Ca2+ decay, whereas SNX17 overexpression using vectors elicited the opposite effects. Moreover, the protein level of SERCA2a was significantly decreased by silencing SNX17. Immunohistochemistry indicated that SNX17 and SERCA2a were co-localized, and co-immunoprecipitation revealed the binding between the phox-homology domain of SNX17 and SERCA2a protein. Furthermore, lysosome inhibitor chloroquine prevented SNX17 silencing-induced reduction of SERCA2a protein level. CONCLUSION Abnormal downregulation of SNX17 contributes to ischemic damages of cardiac electrophysiology and contractile function. SNX17 is an endogenous anti-arrhythmic factor acting by preserving functional SERCA2a protein in MI thereby offering a new strategy for the management of MI to alleviate ischemic myocardial injuries.
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Affiliation(s)
- Dandan Zhao
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Xuelian Li
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Haihai Liang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Nan Zheng
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Zhenwei Pan
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Yuhong Zhou
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Xiao Liu
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Ming Qian
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Bozhi Xu
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Ying Zhang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Ying Feng
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Muge Qili
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Qiuxia Wu
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China
| | - Baofeng Yang
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China.
| | - Hongli Shan
- Department of Pharmacology (State-Province Key Laboratories of Biomedicine-Pharmaceutics of China, Key Laboratory of Cardiovascular Research, Ministry of Education), College of Pharmacy, Harbin Medical University, Harbin, China.
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15
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Xu J, Kozlov G, McPherson PS, Gehring K. A PH-like domain of the Rab12 guanine nucleotide exchange factor DENND3 binds actin and is required for autophagy. J Biol Chem 2018; 293:4566-4574. [PMID: 29352104 DOI: 10.1074/jbc.ra117.001446] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Revised: 01/08/2018] [Indexed: 01/22/2023] Open
Abstract
Rab GTPases are key regulators of membrane trafficking, and many are activated by guanine nucleotide exchange factors bearing a differentially expressed in normal and neoplastic cells (DENN) domain. By activating the small GTPase Rab12, DENN domain-containing protein 3 (DENND3) functions in autophagy. Here, we identified a structural domain (which we name PHenn) containing a pleckstrin homology subdomain that binds actin and is required for DENND3 function in autophagy. We found that a hydrophobic patch on an extended β-turn of the PHenn domain mediates an intramolecular interaction with the DENN domain of DENND3. We also show that DENND3 binds actin through a surface of positively charged residues on the PHenn domain. Substitutions that blocked either DENN or actin binding compromised the role of DENND3 in autophagy. These results provide new mechanistic insight into the structural determinants regulating DENND3 in autophagy and lay the foundation for future investigations of the DENN protein family.
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Affiliation(s)
- Jie Xu
- From the Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada and
| | - Guennadi Kozlov
- the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
| | - Peter S McPherson
- From the Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec H3A 2B4, Canada and
| | - Kalle Gehring
- the Department of Biochemistry, McGill Centre for Structural Biology, McGill University, Montreal, Quebec H3G 0B1, Canada
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16
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Lai MY, Lau YL. Screening and identification of host proteins interacting with Toxoplasma gondii SAG2 by yeast two-hybrid assay. Parasit Vectors 2017; 10:456. [PMID: 28969712 PMCID: PMC5625703 DOI: 10.1186/s13071-017-2387-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 09/17/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The identification of receptors or binding partners of Toxoplasma gondii from humans is an essential activity. Many proteins involved in T. gondii invasion have been characterized, and their contribution for parasite entry has been proposed. However, their molecular interactions remain unclear. RESULTS Yeast two-hybrid (Y2H) experiment was used to identify the binding partners of surface antigens of T. gondii by using SAG2 as bait. Colony PCR was performed and positive clones were sent for sequencing to confirm their identity. The yeast plasmids for true positive clones were rescued by transformation into E. coli TOP 10F' cells. The interplay between bait and prey was confirmed by β-galactosidase assay and co-immunoprecipitation experiment. We detected 20 clones interacting with SAG2 based on a series of the selection procedures. Following the autoactivation and toxicity tests, SAG2 was proven to be a suitable candidate as a bait. Thirteen clones were further examined by small scale Y2H experiment. The results indicated that a strong interaction existed between Homo sapiens zinc finger protein and SAG2, which could activate the expressions of the reporter genes in diploid yeast. Co-immunoprecipitation experiment result indicated the binding between this prey and SAG2 protein was significant (Mann-Whitney U-test: Z = -1.964, P = 0.05). CONCLUSIONS Homo sapiens zinc finger protein was found to interact with SAG2. To improve the understanding of this prey protein's function, advanced investigations need to be carried out.
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Affiliation(s)
- Meng-Yee Lai
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - Yee-Ling Lau
- Department of Parasitology, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia
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17
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Abstract
The disease known as cerebral cavernous malformations mostly occurs in the central nervous system, and their typical histological presentations are multiple lumen formation and vascular leakage at the brain capillary level, resulting in disruption of the blood-brain barrier. These abnormalities result in severe neurological symptoms such as seizures, focal neurological deficits and hemorrhagic strokes. CCM research has identified ‘loss of function’ mutations of three ccm genes responsible for the disease and also complex regulation of multiple signaling pathways including the WNT/β-catenin pathway, TGF-β and Notch signaling by the ccm genes. Although CCM research is a relatively new and small scientific field, as CCM research has the potential to regulate systemic blood vessel permeability and angiogenesis including that of the blood-brain barrier, this field is growing rapidly. In this review, I will provide a brief overview of CCM pathogenesis and function of ccm genes based on recent progress in CCM research. [BMB Reports 2016; 49(5): 255-262]
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Affiliation(s)
- Jaehong Kim
- Department of Biochemistry, School of Medicine, Gachon University, Incheon 21936; Department of Health Sciences and Technology, Gachon Advanced Institute for Health Science and Technology, Gachon University, Incheon 21999, Korea
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18
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Myosin MyTH4-FERM structures highlight important principles of convergent evolution. Proc Natl Acad Sci U S A 2016; 113:E2906-15. [PMID: 27166421 DOI: 10.1073/pnas.1600736113] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosins containing MyTH4-FERM (myosin tail homology 4-band 4.1, ezrin, radixin, moesin, or MF) domains in their tails are found in a wide range of phylogenetically divergent organisms, such as humans and the social amoeba Dictyostelium (Dd). Interestingly, evolutionarily distant MF myosins have similar roles in the extension of actin-filled membrane protrusions such as filopodia and bind to microtubules (MT), suggesting that the core functions of these MF myosins have been highly conserved over evolution. The structures of two DdMyo7 signature MF domains have been determined and comparison with mammalian MF structures reveals that characteristic features of MF domains are conserved. However, across millions of years of evolution conserved class-specific insertions are seen to alter the surfaces and the orientation of subdomains with respect to each other, likely resulting in new sites for binding partners. The MyTH4 domains of Myo10 and DdMyo7 bind to MT with micromolar affinity but, surprisingly, their MT binding sites are on opposite surfaces of the MyTH4 domain. The structural analysis in combination with comparison of diverse MF myosin sequences provides evidence that myosin tail domain features can be maintained without strict conservation of motifs. The results illustrate how tuning of existing features can give rise to new structures while preserving the general properties necessary for myosin tails. Thus, tinkering with the MF domain enables it to serve as a multifunctional platform for cooperative recruitment of various partners, allowing common properties such as autoinhibition of the motor and microtubule binding to arise through convergent evolution.
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19
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Structural analysis of the KRIT1 ankyrin repeat and FERM domains reveals a conformationally stable ARD-FERM interface. J Struct Biol 2015; 192:449-456. [PMID: 26458359 PMCID: PMC4651721 DOI: 10.1016/j.jsb.2015.10.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 10/06/2015] [Accepted: 10/08/2015] [Indexed: 01/07/2023]
Abstract
Cerebral cavernous malformations (CCM) are vascular dysplasias that usually occur in the brain and are associated with mutations in the KRIT1/CCM1, CCM2/MGC4607/OSM/Malcavernin, and PDCD10/CCM3/TFAR15 genes. Here we report the 2.9 Å crystal structure of the ankyrin repeat domain (ARD) and FERM domain of the protein product of KRIT1 (KRIT1; Krev interaction trapped 1). The crystal structure reveals that the KRIT1 ARD contains 4 ankyrin repeats. There is an unusual conformation in the ANK4 repeat that is stabilized by Trp-404, and the structure reveals a solvent exposed ankyrin groove. Domain orientations of the three copies within the asymmetric unit suggest a stable interaction between KRIT1 ARD and FERM domains, indicating a globular ARD-FERM module. This resembles the additional F0 domain found N-terminal to the FERM domain of talin. Structural analysis of KRIT1 ARD-FERM highlights surface regions of high evolutionary conservation, and suggests potential sites that could mediate interaction with binding partners. The structure therefore provides a better understanding of KRIT1 at the molecular level.
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20
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Osborne DG, Piotrowski JT, Dick CJ, Zhang JS, Billadeau DD. SNX17 affects T cell activation by regulating TCR and integrin recycling. THE JOURNAL OF IMMUNOLOGY 2015; 194:4555-66. [PMID: 25825439 DOI: 10.4049/jimmunol.1402734] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2014] [Accepted: 03/02/2015] [Indexed: 11/19/2022]
Abstract
A key component in T cell activation is the endosomal recycling of receptors to the cell surface, thereby allowing continual integration of signaling and Ag recognition. One protein potentially involved in TCR transport is sorting nexin 17 (SNX17). SNX proteins have been found to bind proteins involved in T cell activation, but specifically the role of SNX17 in receptor recycling and T cell activation is unknown. Using immunofluorescence, we find that SNX17 colocalizes with TCR and localizes to the immune synapse in T- conjugates. Significantly, knockdown of the SNX17 resulted in fewer T-APC conjugates, lower CD69, TCR, and LFA-1 surface expression, as well as lower overall TCR recycling compared with control T cells. Lastly, we identified the 4.1/ezrin/radixin/moesin domain of SNX17 as being responsible in the binding and trafficking of TCR and LFA-1 to the cell surface. These data suggest that SNX17 plays a role in the maintenance of normal surface levels of activating receptors and integrins to permit optimum T cell activation at the immune synapse.
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Affiliation(s)
- Douglas G Osborne
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905;Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905; andDivision of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Joshua T Piotrowski
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905;Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905; andDivision of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Christopher J Dick
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905;Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905; andDivision of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Jin-San Zhang
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905;Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905; andDivision of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Daniel D Billadeau
- Department of Immunology, Mayo Clinic College of Medicine, Rochester, MN 55905;Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Rochester, MN 55905; andDivision of Oncology Research, Schulze Center for Novel Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
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21
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Fisher OS, Liu W, Zhang R, Stiegler AL, Ghedia S, Weber JL, Boggon TJ. Structural basis for the disruption of the cerebral cavernous malformations 2 (CCM2) interaction with Krev interaction trapped 1 (KRIT1) by disease-associated mutations. J Biol Chem 2014; 290:2842-53. [PMID: 25525273 DOI: 10.1074/jbc.m114.616433] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Familial cerebral cavernous malformations (CCMs) are predominantly neurovascular lesions and are associated with mutations within the KRIT1, CCM2, and PDCD10 genes. The protein products of KRIT1 and CCM2 (Krev interaction trapped 1 (KRIT1) and cerebral cavernous malformations 2 (CCM2), respectively) directly interact with each other. Disease-associated mutations in KRIT1 and CCM2 mostly result in loss of their protein products, although rare missense point mutations can also occur. From gene sequencing of patients known or suspected to have one or more CCMs, we discover a series of missense point mutations in KRIT1 and CCM2 that result in missense mutations in the CCM2 and KRIT1 proteins. To place these mutations in the context of the molecular level interactions of CCM2 and KRIT1, we map the interaction of KRIT1 and CCM2 and find that the CCM2 phosphotyrosine binding (PTB) domain displays a preference toward the third of the three KRIT1 NPX(Y/F) motifs. We determine the 2.75 Å co-crystal structure of the CCM2 PTB domain with a peptide corresponding to KRIT1(NPX(Y/F)3), revealing a Dab-like PTB fold for CCM2 and its interaction with KRIT1(NPX(Y/F)3). We find that several disease-associated missense mutations in CCM2 have the potential to interrupt the KRIT1-CCM2 interaction by destabilizing the CCM2 PTB domain and that a KRIT1 mutation also disrupts this interaction. We therefore provide new insights into the architecture of CCM2 and how the CCM complex is disrupted in CCM disease.
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Affiliation(s)
- Oriana S Fisher
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Weizhi Liu
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Rong Zhang
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Amy L Stiegler
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520
| | - Sondhya Ghedia
- the Department of Clinical Genetics, Royal North Shore Hospital, Pacific Highway, St. Leonards, New South Wales 2065, Australia, and
| | | | - Titus J Boggon
- From the Department of Pharmacology, Yale University School of Medicine, New Haven, Connecticut 06520,
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