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Nan Y, Chen W, Chen F, Wei L, Zeng A, Lin X, Zhou W, Yang Y, Li Q. Endosome mediated nucleocytoplasmic trafficking and endomembrane allocation is crucial to polyglutamine toxicity. Cell Biol Toxicol 2024; 40:48. [PMID: 38900277 PMCID: PMC11189978 DOI: 10.1007/s10565-024-09891-4] [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: 12/11/2023] [Accepted: 06/03/2024] [Indexed: 06/21/2024]
Abstract
Aggregation of aberrant proteins is a common pathological hallmark in neurodegeneration such as polyglutamine (polyQ) and other repeat-expansion diseases. Here through overexpression of ataxin3 C-terminal polyQ expansion in Drosophila gut enterocytes, we generated an intestinal obstruction model of spinocerebellar ataxia type3 (SCA3) and reported a new role of nuclear-associated endosomes (NAEs)-the delivery of polyQ to the nucleoplasm. In this model, accompanied by the prominently increased RAB5-positive NAEs are abundant nucleoplasmic reticulum enriched with polyQ, abnormal nuclear envelope invagination, significantly reduced endoplasmic reticulum, indicating dysfunctional nucleocytoplasmic trafficking and impaired endomembrane organization. Consistently, Rab5 but not Rab7 RNAi further decreased polyQ-related NAEs, inhibited endomembrane disorganization, and alleviated disease model. Interestingly, autophagic proteins were enriched in polyQ-related NAEs and played non-canonical autophagic roles as genetic manipulation of autophagic molecules exhibited differential impacts on NAEs and SCA3 toxicity. Namely, the down-regulation of Atg1 or Atg12 mitigated while Atg5 RNAi aggravated the disease phenotypes both in Drosophila intestines and compound eyes. Our findings, therefore, provide new mechanistic insights and underscore the fundamental roles of endosome-centered nucleocytoplasmic trafficking and homeostatic endomembrane allocation in the pathogenesis of polyQ diseases.
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Affiliation(s)
- Yuyu Nan
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410000, China
- Department of Critical Care Units, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, 311121, China
| | - Wenfeng Chen
- Institute of Life Sciences, Fuzhou University, Fuzhou, Fujian Province, 350108, China
| | - Fei Chen
- Institute of Life Sciences, Fuzhou University, Fuzhou, Fujian Province, 350108, China
| | - Lili Wei
- Guangxi Clinical Research Center for Neurological Diseases, Guilin, Guangxi, 541001, China
| | - Aiyuan Zeng
- Department of Neurology, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin, Guangxi, 541004, China
| | - Xiaohui Lin
- Department of Neurology, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin, Guangxi, 541004, China
| | - Wenbin Zhou
- Department of Neurology, Xiangya Hospital, Central South University, Changsha, 410000, China
| | - Yufeng Yang
- Institute of Life Sciences, Fuzhou University, Fuzhou, Fujian Province, 350108, China.
| | - Qinghua Li
- Department of Neurology, The Affiliated Hospital of Guilin Medical University, Guilin, Guangxi, 541001, China.
- Guangxi Key Laboratory of Brain and Cognitive Neuroscience, Guilin, Guangxi, 541004, China.
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2
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Langdon CG. Nuclear PTEN's Functions in Suppressing Tumorigenesis: Implications for Rare Cancers. Biomolecules 2023; 13:biom13020259. [PMID: 36830628 PMCID: PMC9953540 DOI: 10.3390/biom13020259] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2022] [Revised: 01/25/2023] [Accepted: 01/28/2023] [Indexed: 01/31/2023] Open
Abstract
Phosphatase and tensin homolog (PTEN) encodes a tumor-suppressive phosphatase with both lipid and protein phosphatase activity. The tumor-suppressive functions of PTEN are lost through a variety of mechanisms across a wide spectrum of human malignancies, including several rare cancers that affect pediatric and adult populations. Originally discovered and characterized as a negative regulator of the cytoplasmic, pro-oncogenic phosphoinositide-3-kinase (PI3K) pathway, PTEN is also localized to the nucleus where it can exert tumor-suppressive functions in a PI3K pathway-independent manner. Cancers can usurp the tumor-suppressive functions of PTEN to promote oncogenesis by disrupting homeostatic subcellular PTEN localization. The objective of this review is to describe the changes seen in PTEN subcellular localization during tumorigenesis, how PTEN enters the nucleus, and the spectrum of impacts and consequences arising from disrupted PTEN nuclear localization on tumor promotion. This review will highlight the immediate need in understanding not only the cytoplasmic but also the nuclear functions of PTEN to gain more complete insights into how important PTEN is in preventing human cancers.
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Affiliation(s)
- Casey G. Langdon
- Department of Pediatrics, Darby Children’s Research Institute, Medical University of South Carolina, Charleston, SC 29425, USA; ; Tel.: +1-(843)-792-9289
- Hollings Cancer Center, Medical University of South Carolina, Charleston, SC 29425, USA
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3
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The Role of microRNAs in the Mammary Gland Development, Health, and Function of Cattle, Goats, and Sheep. Noncoding RNA 2021; 7:ncrna7040078. [PMID: 34940759 PMCID: PMC8708473 DOI: 10.3390/ncrna7040078] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/07/2021] [Accepted: 12/10/2021] [Indexed: 02/07/2023] Open
Abstract
Milk is an integral and therefore complex structural element of mammalian nutrition. Therefore, it is simple to conclude that lactation, the process of producing milk, is as complex as the mammary gland, the organ responsible for this biochemical activity. Nutrition, genetics, epigenetics, disease pathogens, climatic conditions, and other environmental variables all impact breast productivity. In the last decade, the number of studies devoted to epigenetics has increased dramatically. Reports are increasingly describing the direct participation of microRNAs (miRNAs), small noncoding RNAs that regulate gene expression post-transcriptionally, in the regulation of mammary gland development and function. This paper presents a summary of the current state of knowledge about the roles of miRNAs in mammary gland development, health, and functions, particularly during lactation. The significance of miRNAs in signaling pathways, cellular proliferation, and the lipid metabolism in agricultural ruminants, which are crucial in light of their role in the nutrition of humans as consumers of dairy products, is discussed.
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Aagab acts as a novel regulator of NEDD4-1-mediated Pten nuclear translocation to promote neurological recovery following hypoxic-ischemic brain damage. Cell Death Differ 2021; 28:2367-2384. [PMID: 33712741 PMCID: PMC8328997 DOI: 10.1038/s41418-021-00757-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 01/31/2023] Open
Abstract
Hypoxic-ischemic encephalopathy (HIE) is a main cause of mortality and severe neurologic impairment in the perinatal and neonatal period. However, few satisfactory therapeutic strategies are available. Here, we reported that a rapid nuclear translocation of phosphatase and tensin homolog deleted on chromosome TEN (PTEN) is an essential step in hypoxic-ischemic brain damage (HIBD)- and oxygen-glucose deprivation (OGD)-induced neuronal injures both in vivo and in vitro. In addition, we found that OGD-induced nuclear translocation of PTEN is dependent on PTEN mono-ubiquitination at the lysine 13 residue (K13) that is mediated by neural precursor cell expressed developmentally downregulated protein 4-1 (NEDD4-1). Importantly, we for the first time identified α- and γ-adaptin binding protein (Aagab) as a novel NEDD4-1 regulator to regulate the level of NEDD4-1, subsequently mediating Pten nuclear translocation. Finally, we demonstrated that genetic upregulation of Aagab or application of Tat-K13 peptide (a short interference peptide that flanks K13 residue of PTEN) not only reduced Pten nuclear translocation, but also significantly alleviated the deficits of myodynamia, motor and spatial learning and memory in HIBD model rats. These results suggest that Aagab may serve as a regulator of NEDD4-1-mediated Pten nuclear translocation to promote functional recovery following HIBD in neonatal rats, and provide a new potential therapeutic target to guide the clinical treatment for HIE.
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Moghbeli M. Molecular interactions of miR-338 during tumor progression and metastasis. Cell Mol Biol Lett 2021; 26:13. [PMID: 33827418 PMCID: PMC8028791 DOI: 10.1186/s11658-021-00257-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2021] [Accepted: 03/25/2021] [Indexed: 02/08/2023] Open
Abstract
Background Cancer, as one of the main causes of human deaths, is currently a significant global health challenge. Since the majority of cancer-related deaths are associated with late diagnosis, it is necessary to develop minimally invasive early detection markers to manage and reduce mortality rates. MicroRNAs (miRNAs), as highly conserved non-coding RNAs, target the specific mRNAs which are involved in regulation of various fundamental cellular processes such as cell proliferation, death, and signaling pathways. MiRNAs can also be regulated by long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). They are highly stable in body fluids and have tumor-specific expression profiles, which suggest their suitability as efficient non-invasive diagnostic and prognostic tumor markers. Aberrant expression of miR-338 has been widely reported in different cancers. It regulates cell proliferation, migration, angiogenesis, and apoptosis in tumor cells. Main body In the present review, we have summarized all miR-338 interactions with other non-coding RNAs (ncRNAs) and associated signaling pathways to clarify the role of miR-338 during tumor progression. Conclusions It was concluded that miR-338 mainly functions as a tumor suppressor in different cancers. There were also significant associations between miR-338 and other ncRNAs in tumor cells. Moreover, miR-338 has a pivotal role during tumor progression using the regulation of WNT, MAPK, and PI3K/AKT signaling pathways. This review highlights miR-338 as a pivotal ncRNA in biology of tumor cells.
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Affiliation(s)
- Meysam Moghbeli
- Department of Medical Genetics and Molecular Medicine, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
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6
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Multifaceted Regulation of PTEN Subcellular Distributions and Biological Functions. Cancers (Basel) 2019; 11:cancers11091247. [PMID: 31454965 PMCID: PMC6770588 DOI: 10.3390/cancers11091247] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 08/15/2019] [Accepted: 08/19/2019] [Indexed: 12/19/2022] Open
Abstract
Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a tumor suppressor gene frequently found to be inactivated in over 30% of human cancers. PTEN encodes a 54-kDa lipid phosphatase that serves as a gatekeeper of the phosphoinositide 3-kinase pathway involved in the promotion of multiple pro-tumorigenic phenotypes. Although the PTEN protein plays a pivotal role in carcinogenesis, cumulative evidence has implicated it as a key signaling molecule in several other diseases as well, such as diabetes, Alzheimer's disease, and autism spectrum disorders. This finding suggests that diverse cell types, especially differentiated cells, express PTEN. At the cellular level, PTEN is widely distributed in all subcellular compartments and organelles. Surprisingly, the cytoplasmic compartment, not the plasma membrane, is the predominant subcellular location of PTEN. More recently, the finding of a secreted 'long' isoform of PTEN and the presence of PTEN in the cell nucleus further revealed unexpected biological functions of this multifaceted molecule. At the regulatory level, PTEN activity, stability, and subcellular distribution are modulated by a fascinating array of post-translational modification events, including phosphorylation, ubiquitination, and sumoylation. Dysregulation of these regulatory mechanisms has been observed in various human diseases. In this review, we provide an up-to-date overview of the knowledge gained in the last decade on how different functional domains of PTEN regulate its biological functions, with special emphasis on its subcellular distribution. This review also highlights the findings of published studies that have reported how mutational alterations in specific PTEN domains can lead to pathogenesis in humans.
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Murray SS, Wong AW, Yang J, Li Y, Putz U, Tan SS, Howitt J. Ubiquitin Regulation of Trk Receptor Trafficking and Degradation. Mol Neurobiol 2018; 56:1628-1636. [PMID: 29911254 DOI: 10.1007/s12035-018-1179-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Accepted: 06/04/2018] [Indexed: 10/28/2022]
Abstract
The regulation of Trk receptors is critical for orchestrating multiple signalling pathways required for developing and maintaining neuronal networks. Activation of Trk receptors results in signalling, internalisation and subsequent degradation of the protein. Although ubiquitination of TrkA by Nedd4-2 has been identified as an important degradation pathway, much less is known about the pathways regulating the degradation of TrkB and TrkC. Critical to the interaction between TrkA and Nedd4-2 is a PPxY motif present within TrkA but absent in TrkB and TrkC. Given the absence of this interaction motif, it remains to be determined how TrkB and TrkC are ubiquitinated. Here we report that the adaptor protein Ndfip1 can interact with all three Trk receptors and show for TrkB the recruitment of Nedd4-2 through PPxY motifs present in Ndfip1. Ndfip1 mediates the ubiquitination of TrkB, resulting in receptor trafficking predominantly on Rab7 containing late endosomes, highlighting a pathway for TrkB degradation at the lysosome. In vitro, overexpression of Ndfip1 increased TrkB ubiquitination and decreased viability of BDNF-dependent primary neurons. In vivo, conditional genetic deletion of Ndfip1 increased TrkB in the brain and resulted in enlargement of the granular cell layer of the dentate gyrus.
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Affiliation(s)
- S S Murray
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - A W Wong
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Australia
| | - J Yang
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - Y Li
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - U Putz
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - S-S Tan
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia
| | - J Howitt
- Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Australia. .,Department of Health and Medical Sciences, Iverson Health Innovation Institute, Swinburne University of Technology, Hawthorn, Australia.
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Estrogen receptor β, a regulator of androgen receptor signaling in the mouse ventral prostate. Proc Natl Acad Sci U S A 2017; 114:E3816-E3822. [PMID: 28439009 DOI: 10.1073/pnas.1702211114] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
As estrogen receptor β-/- (ERβ-/-) mice age, the ventral prostate (VP) develops increased numbers of hyperplastic, fibroplastic lesions and inflammatory cells. To identify genes involved in these changes, we used RNA sequencing and immunohistochemistry to compare gene expression profiles in the VP of young (2-mo-old) and aging (18-mo-old) ERβ-/- mice and their WT littermates. We also treated young and old WT mice with an ERβ-selective agonist and evaluated protein expression. The most significant findings were that ERβ down-regulates androgen receptor (AR) signaling and up-regulates the tumor suppressor phosphatase and tensin homolog (PTEN). ERβ agonist increased expression of the AR corepressor dachshund family (DACH1/2), T-cadherin, stromal caveolin-1, and nuclear PTEN and decreased expression of RAR-related orphan receptor c, Bcl2, inducible nitric oxide synthase, and IL-6. In the ERβ-/- mouse VP, RNA sequencing revealed that the following genes were up-regulated more than fivefold: Bcl2, clusterin, the cytokines CXCL16 and -17, and a marker of basal/intermediate cells (prostate stem cell antigen) and cytokeratins 4, 5, and 17. The most down-regulated genes were the following: the antioxidant gene glutathione peroxidase 3; protease inhibitors WAP four-disulfide core domain 3 (WFDC3); the tumor-suppressive genes T-cadherin and caveolin-1; the regulator of transforming growth factor β signaling SMAD7; and the PTEN ubiquitin ligase NEDD4. The role of ERβ in opposing AR signaling, proliferation, and inflammation suggests that ERβ-selective agonists may be used to prevent progression of prostate cancer, prevent fibrosis and development of benign prostatic hyperplasia, and treat prostatitis.
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Engineered Exosomes as Vehicles for Biologically Active Proteins. Mol Ther 2017; 25:1269-1278. [PMID: 28412169 DOI: 10.1016/j.ymthe.2017.03.030] [Citation(s) in RCA: 228] [Impact Index Per Article: 32.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 03/20/2017] [Accepted: 03/20/2017] [Indexed: 12/23/2022] Open
Abstract
Exosomes represent an attractive vehicle for the delivery of biomolecules. However, mechanisms for loading functional molecules into exosomes are relatively unexplored. Here we report the use of the evolutionarily conserved late-domain (L-domain) pathway as a mechanism for loading exogenous proteins into exosomes. We demonstrate that labeling of a target protein, Cre recombinase, with a WW tag leads to recognition by the L-domain-containing protein Ndfip1, resulting in ubiquitination and loading into exosomes. Our results show that Ndfip1 expression acts as a molecular switch for exosomal packaging of WW-Cre that can be suppressed using the exosome inhibitor GW4869. When taken up by floxed reporter cells, exosomes containing WW-Cre were capable of inducing DNA recombination, indicating functional delivery of the protein to recipient cells. Engineered exosomes were administered to the brain of transgenic reporter mice using the nasal route to test for intracellular protein delivery in vivo. This resulted in the transport of engineered exosomes predominantly to recipient neurons in a number of brain regions, including the olfactory bulb, cortex, striatum, hippocampus, and cerebellum. The ability to engineer exosomes to deliver biologically active proteins across the blood-brain barrier represents an important step for the development of therapeutics to treat brain diseases.
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Matsuda S, Ichimura M, Ogino M, Nakano N, Minami A, Murai T, Kitagishi Y. Effective PI3K modulators for improved therapy against malignant tumors and for neuroprotection of brain damage after tumor therapy (Review). Int J Oncol 2016; 49:1785-1790. [PMID: 27826621 DOI: 10.3892/ijo.2016.3710] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Accepted: 09/15/2016] [Indexed: 11/06/2022] Open
Abstract
Due to the key role in various cellular processes including cell proliferation and cell survival on many cell types, dysregulation of the PI3K/AKT pathway represents a crucial step of the pathogenesis in many diseases. Furthermore, the tumor suppressor PTEN negatively regulates the PI3K/AKT pathway through its lipid phosphatase activity, which is recognized as one of the most frequently deleted and/or mutated genes in human cancer. Given the pervasive involvement of this pathway, the development of the molecules that modulate this PI3K/AKT signaling has been initiated in studies which focus on the extensive effective drug discovery. Consequently, the PI3K/AKT pathway appears to be an attractive pharmacological target both for cancer therapy and for neurological protection necessary after the therapy. A better understanding of the molecular relations could reveal new targets for treatment development. We review recent studies on the features of PI3K/AKT and PTEN, and their pleiotropic functions relevant to the signaling pathways involved in cancer progress and in neuronal damage by the therapy.
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Affiliation(s)
- Satoru Matsuda
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Mayuko Ichimura
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Mako Ogino
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Noriko Nakano
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Akari Minami
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
| | - Toshiyuki Murai
- Department of Microbiology and Immunology and Department of Genome Biology, Graduate School of Medicine, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasuko Kitagishi
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan
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Rastogi R, Verma JK, Kapoor A, Langsley G, Mukhopadhyay A. Rab5 Isoforms Specifically Regulate Different Modes of Endocytosis in Leishmania. J Biol Chem 2016; 291:14732-46. [PMID: 27226564 DOI: 10.1074/jbc.m116.716514] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Indexed: 11/06/2022] Open
Abstract
Differential functions of Rab5 isoforms in endocytosis are not well characterized. Here, we cloned, expressed, and characterized Rab5a and Rab5b from Leishmania and found that both of them are localized in the early endosome. To understand the role of LdRab5 isoforms in different modes of endocytosis in Leishmania, we generated transgenic parasites overexpressing LdRab5a, LdRab5b, or their dominant-positive (LdRab5a:Q93L and LdRab5b:Q80L) or dominant-negative mutants (LdRab5a:N146I and LdRab5b:N133I). Using LdRab5a or its mutants overexpressing parasites, we found that LdRab5a specifically regulates the fluid-phase endocytosis of horseradish peroxidase and also specifically induced the transport of dextran-Texas Red to the lysosomes. In contrast, cells overexpressing LdRab5b or its mutants showed that LdRab5b explicitly controls receptor-mediated endocytosis of hemoglobin, and overexpression of LdRab5b:WT enhanced the transport of internalized Hb to the lysosomes in comparison with control cells. To unequivocally demonstrate the role of Rab5 isoforms in endocytosis in Leishmania, we tried to generate null-mutants of LdRab5a and LdRab5b parasites, but both were lethal indicating their essential functions in parasites. Therefore, we used heterozygous LdRab5a(+/-) and LdRab5b(+/-) cells. LdRab5a(+/-) Leishmania showed 50% inhibition of HRP uptake, but hemoglobin endocytosis was uninterrupted. In contrast, about 50% inhibition of Hb endocytosis was observed in LdRab5b(+/-) cells without any significant effect on HRP uptake. Finally, we tried to identify putative LdRab5a and LdRab5b effectors. We found that LdRab5b interacts with clathrin heavy chain and hemoglobin receptor. However, LdRab5a failed to interact with the clathrin heavy chain, and interaction with hemoglobin receptor was significantly less. Thus, our results showed that LdRab5a and LdRab5b differentially regulate fluid phase and receptor-mediated endocytosis in Leishmania.
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Affiliation(s)
- Ruchir Rastogi
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India and
| | - Jitender Kumar Verma
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India and
| | - Anjali Kapoor
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India and
| | - Gordon Langsley
- the INSERM U1016, CNRS UMR8104, Cochin Institute, 75014 Paris, France
| | - Amitabha Mukhopadhyay
- From the National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi 110067, India and
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Abstract
Discovered in 1997, PTEN remains one of the most studied tumor suppressors. In this issue of Methods in Molecular Biology, we assembled a series of papers describing various clinical and experimental approaches to studying PTEN function. Due to its broad expression, regulated subcellular localization, and intriguing phosphatase activity, methodologies aimed at PTEN study have often been developed in the context of mutations affecting various aspects of its regulation, found in patients burdened with PTEN loss-driven tumors. PTEN's extensive posttranslational modifications and dynamic localization pose unique challenges for studying PTEN features in isolation and necessitate considerable development of experimental systems to enable controlled characterization. Nevertheless, ongoing efforts towards the development of PTEN knockout and knock-in animals and cell lines, antibodies, and enzymatic assays have facilitated a huge body of work, which continues to unravel the fascinating biology of PTEN.
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Besse A, Sana J, Lakomy R, Kren L, Fadrus P, Smrcka M, Hermanova M, Jancalek R, Reguli S, Lipina R, Svoboda M, Slampa P, Slaby O. MiR-338-5p sensitizes glioblastoma cells to radiation through regulation of genes involved in DNA damage response. Tumour Biol 2015; 37:7719-27. [PMID: 26692101 DOI: 10.1007/s13277-015-4654-x] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 12/14/2015] [Indexed: 01/28/2023] Open
Abstract
Glioblastoma multiforme (GBM) is the most aggressive form of brain tumor. Despite radical surgery and radiotherapy supported by chemotherapy, the disease still remains incurable with an extremely low median survival rate of 12-15 months from the time of initial diagnosis. The main cause of treatment failure is considered to be the presence of cells that are resistant to the treatment. MicroRNAs (miRNAs) as regulators of gene expression are involved in the tumor pathogenesis, including GBM. MiR-338 is a brain-specific miRNA which has been described to target pathways involved in proliferation and differentiation. In our study, miR-338-3p and miR-338-5p were differentially expressed in GBM tissue in comparison to non-tumor brain tissue. Overexpression of miR-338-3p with miRNA mimic did not show any changes in proliferation rates in GBM cell lines (A172, T98G, U87MG). On the other hand, pre-miR-338-5p notably decreased proliferation and caused cell cycle arrest. Since radiation is currently the main treatment modality in GBM, we combined overexpression of pre-miR-338-5p with radiation, which led to significantly decreased cell proliferation, increased cell cycle arrest, and apoptosis in comparison to irradiation-only cells. To better elucidate the mechanism of action, we performed gene expression profiling analysis that revealed targets of miR-338-5p being Ndfip1, Rheb, and ppp2R5a. These genes have been described to be involved in DNA damage response, proliferation, and cell cycle regulation. To our knowledge, this is the first study to describe the role of miR-338-5p in GBM and its potential to improve the sensitivity of GBM to radiation.
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Affiliation(s)
- Andrej Besse
- Masaryk Memorial Cancer Institute, Department of Comprehensive Cancer Care, Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Central European Institute of Technology (CEITEC), Masaryk University, University Campus Bohunice, Building A3, Kamenice 5, 625 00, Brno, Czech Republic
| | - Jiri Sana
- Masaryk Memorial Cancer Institute, Department of Comprehensive Cancer Care, Faculty of Medicine, Masaryk University, Brno, Czech Republic.,Central European Institute of Technology (CEITEC), Masaryk University, University Campus Bohunice, Building A3, Kamenice 5, 625 00, Brno, Czech Republic
| | - Radek Lakomy
- Masaryk Memorial Cancer Institute, Department of Comprehensive Cancer Care, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Leos Kren
- University Hospital Brno, Department of Pathology, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Pavel Fadrus
- University Hospital Brno, Department of Neurosurgery, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Martin Smrcka
- University Hospital Brno, Department of Neurosurgery, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Marketa Hermanova
- First Department of Pathological Anatomy, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Radim Jancalek
- Department of Neurosurgery, St. Anne's University Hospital and Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Stefan Reguli
- Department of Neurosurgery, University Hospital Ostrava, Ostrava, Czech Republic
| | - Radim Lipina
- Department of Neurosurgery, University Hospital Ostrava, Ostrava, Czech Republic
| | - Marek Svoboda
- Masaryk Memorial Cancer Institute, Department of Comprehensive Cancer Care, Faculty of Medicine, Masaryk University, Brno, Czech Republic
| | - Pavel Slampa
- Department of Radiation Oncology, Memorial Cancer Institute, Brno, Czech Republic
| | - Ondrej Slaby
- Masaryk Memorial Cancer Institute, Department of Comprehensive Cancer Care, Faculty of Medicine, Masaryk University, Brno, Czech Republic. .,Central European Institute of Technology (CEITEC), Masaryk University, University Campus Bohunice, Building A3, Kamenice 5, 625 00, Brno, Czech Republic.
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Howitt J, Low LH, Putz U, Doan A, Lackovic J, Goh CP, Gunnersen J, Silke J, Tan SS. Ndfip1 represses cell proliferation by controlling Pten localization and signaling specificity. J Mol Cell Biol 2015; 7:119-31. [PMID: 25801959 DOI: 10.1093/jmcb/mjv020] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2014] [Accepted: 12/28/2014] [Indexed: 01/16/2023] Open
Abstract
Pten controls a signaling axis that is implicated to regulate cell proliferation, growth, survival, migration, and metabolism. The molecular mechanisms underlying the specificity of Pten responses to such diverse cellular functions are currently poorly understood. Here we report the control of Pten activity and signaling specificity during the cell cycle by Ndfip1 regulation of Pten spatial distribution. Genetic deletion of Ndfip1 resulted in a loss of Pten nuclear compartmentalization and increased cell proliferation, despite cytoplasmic Pten remaining active in regulating PI3K/Akt signaling. Cells lacking nuclear Pten were found to have dysregulated levels of Plk1 and cyclin D1 that could drive cell proliferation. In vivo, transgene expression of Ndfip1 in the developing brain increased nuclear Pten and lengthened the cell cycle of neuronal progenitors, resulting in microencephaly. Our results show that local partitioning of Pten from the cytoplasm to the nucleus represents a key mechanism contributing to the specificity of Pten signaling during cell proliferation.
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Affiliation(s)
- Jason Howitt
- Brain Development and Regeneration Division, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ley-Hian Low
- Brain Development and Regeneration Division, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Ulrich Putz
- Brain Development and Regeneration Division, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Anh Doan
- Brain Development and Regeneration Division, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jenny Lackovic
- Brain Development and Regeneration Division, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Choo-Peng Goh
- Brain Development and Regeneration Division, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Jenny Gunnersen
- Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - John Silke
- Cell Signalling and Cell Death Laboratory, Walter and Eliza Hall Institute, The University of Melbourne, Parkville, Victoria 3010, Australia
| | - Seong-Seng Tan
- Brain Development and Regeneration Division, Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria 3010, Australia
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Low LH, Chow YL, Li Y, Goh CP, Putz U, Silke J, Ouchi T, Howitt J, Tan SS. Nedd4 family interacting protein 1 (Ndfip1) is required for ubiquitination and nuclear trafficking of BRCA1-associated ATM activator 1 (BRAT1) during the DNA damage response. J Biol Chem 2015; 290:7141-50. [PMID: 25631046 PMCID: PMC4358134 DOI: 10.1074/jbc.m114.613687] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2014] [Revised: 01/14/2015] [Indexed: 12/20/2022] Open
Abstract
During injury, cells are vulnerable to apoptosis from a variety of stress conditions including DNA damage causing double-stranded breaks. Without repair, these breaks lead to aberrations in DNA replication and transcription, leading to apoptosis. A major response to DNA damage is provided by the protein kinase ATM (ataxia telangiectasia mutated) that is capable of commanding a plethora of signaling networks for DNA repair, cell cycle arrest, and even apoptosis. A key element in the DNA damage response is the mobilization of activating proteins into the cell nucleus to repair damaged DNA. BRAT1 is one of these proteins, and it functions as an activator of ATM by maintaining its phosphorylated status while also keeping other phosphatases at bay. However, it is unknown how BRAT1 is trafficked into the cell nucleus to maintain ATM phosphorylation. Here we demonstrate that Ndfip1-mediated ubiquitination of BRAT1 leads to BRAT1 trafficking into the cell nucleus. Without Ndfip1, BRAT1 failed to translocate to the nucleus. Under genotoxic stress, cells showed increased expression of both Ndfip1 and phosphorylated ATM. Following brain injury, neurons show increased expression of Ndfip1 and nuclear translocation of BRAT1. These results point to Ndfip1 as a sensor protein during cell injury and Ndfip1 up-regulation as a cue for BRAT1 ubiquitination by Nedd4 E3 ligases, followed by nuclear translocation of BRAT1.
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Affiliation(s)
- Ley-Hian Low
- From the Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Yuh-Lit Chow
- From the Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Yijia Li
- From the Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Choo-Peng Goh
- From the Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3010 Victoria, Australia
| | - Ulrich Putz
- From the Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3010 Victoria, Australia
| | - John Silke
- the Walter & Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Parkville, 3010 Victoria, Australia, and
| | - Toru Ouchi
- the Department of Cancer Genetics, Roswell Park Cancer Institute, Elm & Carlton Streets, Buffalo, New York 14263
| | - Jason Howitt
- From the Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3010 Victoria, Australia,
| | - Seong-Seng Tan
- From the Florey Institute of Neuroscience and Mental Health, University of Melbourne, Parkville, 3010 Victoria, Australia,
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