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Abstract
The Golgi apparatus is a central intracellular membrane-bound organelle with key functions in trafficking, processing, and sorting of newly synthesized membrane and secretory proteins and lipids. To best perform these functions, Golgi membranes form a unique stacked structure. The Golgi structure is dynamic but tightly regulated; it undergoes rapid disassembly and reassembly during the cell cycle of mammalian cells and is disrupted under certain stress and pathological conditions. In the past decade, significant amount of effort has been made to reveal the molecular mechanisms that regulate the Golgi membrane architecture and function. Here we review the major discoveries in the mechanisms of Golgi structure formation, regulation, and alteration in relation to its functions in physiological and pathological conditions to further our understanding of Golgi structure and function in health and diseases.
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Affiliation(s)
- Jie Li
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Erpan Ahat
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA
| | - Yanzhuang Wang
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
- Department of Neurology, University of Michigan School of Medicine, Ann Arbor, MI, USA.
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Wang T, Li L, Hong W. SNARE proteins in membrane trafficking. Traffic 2017; 18:767-775. [PMID: 28857378 DOI: 10.1111/tra.12524] [Citation(s) in RCA: 100] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2017] [Revised: 08/25/2017] [Accepted: 08/25/2017] [Indexed: 12/25/2022]
Abstract
SNAREs are the core machinery mediating membrane fusion. In this review, we provide an update on the recent progress on SNAREs regulating membrane fusion events, especially the more detailed fusion processes dissected by well-developed biophysical methods and in vitro single molecule analysis approaches. We also briefly summarize the relevant research from Chinese laboratories and highlight the significant contributions on our understanding of SNARE-mediated membrane trafficking from scientists in China.
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Affiliation(s)
- Tuanlao Wang
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China
| | - Liangcheng Li
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China
| | - Wanjin Hong
- School of Pharmaceutical Sciences, State Key Laboratory of Cellular Stress Biology, Xiamen University, Xiamen, China.,Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Singapore, Singapore
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Al-Maghrabi JA, Butt NS, Anfinan N, Sait K, Sait H, Marzouki A, Khabaz MN. Infrequent Immunohistochemical Expression of Napsin A in Endometrial Carcinomas. Appl Immunohistochem Mol Morphol 2017; 25:632-638. [DOI: 10.1097/pai.0000000000000350] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Lee SH, Yoo HJ, Rim DE, Cui Y, Lee A, Jung ES, Oh ST, Kim JG, Kwon OJ, Kim SY, Jeong SW. Nuclear Expression of GS28 Protein: A Novel Biomarker that Predicts Prognosis in Colorectal Cancers. Int J Med Sci 2017; 14. [PMID: 28638266 PMCID: PMC5479119 DOI: 10.7150/ijms.19368] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Aims: GS28 (Golgi SNARE protein, 28 kDa), a member of the soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) protein family, plays a critical role in mammalian endoplasmic reticulum (ER)-Golgi or intra-Golgi vesicle transport. To date, few researches on the GS28 protein in human cancer tissues have been reported. In this study, we assessed the prognostic value of GS28 in patients with colorectal cancer (CRC). Methods and results: We screened for GS28 expression using immunohistochemistry in 230 surgical CRC specimens. The CRCs were right-sided and left-sided in 28.3% (65/230) and 71.3% (164/230) of patients, respectively. GS28 staining results were available in 214 cases. Among these, there were 26 nuclear predominant cases and 188 non-nuclear predominant cases. Stromal GS28 expression was noted in 152 cases of CRC. GS28 nuclear predominant immunoreactivity was significantly associated with advanced tumour stage (p = 0.045) and marginally associated with perineural invasion (p = 0.064). Decreased GS28 expression in the stromal cells was significantly associated with lymph node metastasis (N stage; p = 0.036). GS28 expression was not associated with epidermal growth factor receptor (EGFR) immunohistochemical positivity or KRAS mutation status. Investigation of the prognostic value of GS28 with Kaplan-Meier analysis revealed a correlation with overall survival (p = 0.004). Cases with GS28 nuclear predominant expression had significantly poorer overall survival than those with a non-nuclear predominant pattern. Conclusions: Taken together, these results indicate that GS28 nuclear predominant expression could serve as a prognostic marker for CRC and may help in identifying aggressive forms of CRC.
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Affiliation(s)
- Sung Hak Lee
- Department of Hospital Pathology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hyung Jae Yoo
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Do Eun Rim
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Yinji Cui
- Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Ahwon Lee
- Department of Hospital Pathology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Eun Sun Jung
- Department of Hospital Pathology, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Seung Taek Oh
- Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jun Gi Kim
- Department of Surgery, Seoul St. Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Oh-Joo Kwon
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Su Young Kim
- Department of Pathology, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Seong-Whan Jeong
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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Cho U, Kim HM, Park HS, Kwon OJ, Lee A, Jeong SW. Nuclear Expression of GS28 Protein: A Novel Biomarker that Predicts Worse Prognosis in Cervical Cancers. PLoS One 2016; 11:e0162623. [PMID: 27611086 PMCID: PMC5017663 DOI: 10.1371/journal.pone.0162623] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/25/2016] [Indexed: 11/18/2022] Open
Abstract
Objective The protein GS28 (28-kDa Golgi SNARE protein) has been described as a SNARE (Soluble N-ethylmaleimide-sensitive factor attachment protein receptors) protein family member that plays a critical role in mammalian ER-Golgi or intra-Golgi vesicle transport. Little is known about the possible roles of GS28 in pathological conditions. The purpose of this study was to evaluate GS28 expression in cervical cancer tissues and explore its correlation with clinicopathological features and prognosis. Methods We investigated GS28 expression in 177 cervical cancer tissues by using immunohistochemistry and evaluated the correlation of GS28 expression with clinicopathological features, the expression of p53 and Bcl-2, and prognosis of cervical cancer patients. Immunoblotting was performed using six freshly frozen cervical cancer tissues to confirm the subcellular localization of GS28. Results Immunoreactivity of GS28 was observed in both nuclear and cytoplasmic compartments of cervical cancer cells. High nuclear expression of GS28 was associated with advanced tumor stages (P = 0.036) and negative expression of p53 (P = 0.036). In multivariate analyses, patients with high nuclear expression of GS28 showed significantly worse overall survival (OS) (hazard ratio = 3.785, P = 0.003) and progression-free survival (PFS) (hazard ratio = 3.019, P = 0.008), compared to those with low or no nuclear expression. It was also a reliable, independent prognostic marker in subgroups of patients with early stage T1 and negative lymph node metastasis in OS (P = 0.008 and 0.019, respectively). The nuclear expression of GS28 was confirmed by immunoblotting. Conclusion High nuclear expression of GS28 is associated with poor prognosis in early-stage cervical cancer patients. GS28 might be a novel prognostic marker and a potential therapeutic target in cervical cancer treatment.
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Affiliation(s)
- Uiju Cho
- Department of Hospital Pathology, St. Vincent’s Hospital, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea
| | - Hae-Mi Kim
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Hong Sik Park
- Department of Hospital Pathology, St. Vincent’s Hospital, College of Medicine, The Catholic University of Korea, Suwon, Republic of Korea
| | - Oh-Joo Kwon
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Ahwon Lee
- Department of Hospital Pathology, Seoul St. Mary’s Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- * E-mail: (SJ); (AL)
| | - Seong-Whan Jeong
- Department of Biochemistry, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
- * E-mail: (SJ); (AL)
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Yan Y, Xu Z, Dai S, Qian L, Sun L, Gong Z. Targeting autophagy to sensitive glioma to temozolomide treatment. J Exp Clin Cancer Res 2016; 35:23. [PMID: 26830677 PMCID: PMC4736617 DOI: 10.1186/s13046-016-0303-5] [Citation(s) in RCA: 221] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2015] [Accepted: 01/28/2016] [Indexed: 02/08/2023] Open
Abstract
Temozolomide (TMZ), an alkylating agent, is widely used for treating primary and recurrent high-grade gliomas. However, the efficacy of TMZ is often limited by the development of resistance. Recently, studies have found that TMZ treatment could induce autophagy, which contributes to therapy resistance in glioma. To enhance the benefit of TMZ in the treatment of glioblastomas, effective combination strategies are needed to sensitize glioblastoma cells to TMZ. In this regard, as autophagy could promote cell survival or autophagic cell death, modulating autophagy using a pharmacological inhibitor, such as chloroquine, or an inducer, such as rapamycin, has received considerably more attention. To understand the effectiveness of regulating autophagy in glioblastoma treatment, this review summarizes reports on glioblastoma treatments with TMZ and autophagic modulators from in vitro and in vivo studies, as well as clinical trials. Additionally, we discuss the possibility of using autophagy regulatory compounds that can sensitive TMZ treatment as a chemotherapy for glioma treatment.
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Affiliation(s)
- Yuanliang Yan
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410008, China.
- Institute of Hospital Pharmacy, Central South University, Changsha, 410008, China.
| | - Zhijie Xu
- Department of Pathology, Xiangya Hospital, Central South University, Changsha, 410008, China.
| | - Shuang Dai
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410008, China.
- Institute of Hospital Pharmacy, Central South University, Changsha, 410008, China.
| | - Long Qian
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410008, China.
- Institute of Hospital Pharmacy, Central South University, Changsha, 410008, China.
| | - Lunquan Sun
- Center for Molecular Medicine, Xiangya Hospital, Key Laboratory of Molecular Radiation Oncology of Hunan Province, Central South University, Changsha, 410008, China.
| | - Zhicheng Gong
- Department of Pharmacy, Xiangya Hospital, Central South University, Changsha, 410008, China.
- Institute of Hospital Pharmacy, Central South University, Changsha, 410008, China.
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Liu YC, Chang PY, Chao CCK. CITED2 silencing sensitizes cancer cells to cisplatin by inhibiting p53 trans-activation and chromatin relaxation on the ERCC1 DNA repair gene. Nucleic Acids Res 2015; 43:10760-81. [PMID: 26384430 PMCID: PMC4678856 DOI: 10.1093/nar/gkv934] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2015] [Accepted: 09/08/2015] [Indexed: 02/07/2023] Open
Abstract
In this study, we show that silencing of CITED2 using small-hairpin RNA (shCITED2) induced DNA damage and reduction of ERCC1 gene expression in HEK293, HeLa and H1299 cells, even in the absence of cisplatin. In contrast, ectopic expression of ERCC1 significantly reduced intrinsic and induced DNA damage levels, and rescued the effects of CITED2 silencing on cell viability. The effects of CITED2 silencing on DNA repair and cell death were associated with p53 activity. Furthermore, CITED2 silencing caused severe elimination of the p300 protein and markers of relaxed chromatin (acetylated H3 and H4, i.e. H3K9Ac and H3K14Ac) in HEK293 cells. Chromatin immunoprecipitation assays further revealed that DNA damage induced binding of p53 along with H3K9Ac or H3K14Ac at the ERCC1 promoter, an effect which was almost entirely abrogated by silencing of CITED2 or p300. Moreover, lentivirus-based CITED2 silencing sensitized HeLa cell line-derived tumor xenografts to cisplatin in immune-deficient mice. These results demonstrate that CITED2/p300 can be recruited by p53 at the promoter of the repair gene ERCC1 in response to cisplatin-induced DNA damage. The CITED2/p300/p53/ERCC1 pathway is thus involved in the cell response to cisplatin and represents a potential target for cancer therapy.
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Affiliation(s)
- Yu-Chin Liu
- Tumor Biology Laboratory, Department of Biochemistry and Molecular Biology, Chang Gung University, 259 Wen-Hua first Road, Gueishan, Taoyuan 333, Taiwan, Republic of China Graduate Institute of Biomedical Sciences, Chang Gung University, 259 Wen-Hua first Road, Gueishan,Taoyuan 333, Taiwan, Republic of China
| | - Pu-Yuan Chang
- Tumor Biology Laboratory, Department of Biochemistry and Molecular Biology, Chang Gung University, 259 Wen-Hua first Road, Gueishan, Taoyuan 333, Taiwan, Republic of China
| | - Chuck C-K Chao
- Tumor Biology Laboratory, Department of Biochemistry and Molecular Biology, Chang Gung University, 259 Wen-Hua first Road, Gueishan, Taoyuan 333, Taiwan, Republic of China Graduate Institute of Biomedical Sciences, Chang Gung University, 259 Wen-Hua first Road, Gueishan,Taoyuan 333, Taiwan, Republic of China
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Suga K, Saito A, Akagawa K. ER stress response in NG108-15 cells involves upregulation of syntaxin 5 expression and reduced amyloid β peptide secretion. Exp Cell Res 2015; 332:11-23. [DOI: 10.1016/j.yexcr.2015.01.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 01/05/2015] [Accepted: 01/07/2015] [Indexed: 01/24/2023]
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Mechanisms of p53 degradation. Clin Chim Acta 2015; 438:139-47. [DOI: 10.1016/j.cca.2014.08.015] [Citation(s) in RCA: 77] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2014] [Revised: 08/13/2014] [Accepted: 08/13/2014] [Indexed: 11/19/2022]
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Wang J, Cai Z, Liu J. Microarray analysis for differentially expressed genes of patients undergoing total knee arthroplasty with ischemia preconditioning. J Orthop Surg Res 2014; 9:133. [PMID: 25496472 PMCID: PMC4298116 DOI: 10.1186/s13018-014-0133-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND Ischemia preconditioning (IPC) has been proved as a powerful method of protecting tissues against ischemia reperfusion insults. We aimed to elucidate the mechanism of IPC in ischemia reperfused tissues. METHODS GSE21164 containing 16 muscle biopsies taken from the operative knee of four IPC-treated patients and four control at the onset of surgery (T¿=¿0) and 1 h into surgery (T¿=¿1) undergoing primary total knee arthroplasty was downloaded from the Gene Expression Omnibus (GEO) database. Differentially expressed genes (DEGs) between IPC group and control were screened with Limma package in R language. KEGG pathway enrichment analysis was performed by the DAVID online tool. Meanwhile, potential regulatory microRNAs (miRNAs) for downregulated DEGs and targets of transcription factors for upregulated DEGs were screened out. Based on the above DEGs, protein-protein interaction (PPI) networks were constructed by the STRING software. RESULTS Significantly upregulated DEGs at T1 were mainly enriched in asthma and p53 signaling pathway. Meanwhile, significantly enriched transcriptional factor NOTCH1 at T1 and GABP at T0 were obtained. Moreover, miRNA analysis showed that targets of miR141/200a were enriched in downregulated DEGs both at T0 and T1. Mostly, RPA1 and JAK2 in PPI network at T1 were with higher degree. CONCLUSIONS In our study, obtained DEGs, regulatory transcriptional factors, and miRNA might play a vital role in the protection of ischemia reperfusion injury. This finding will provide a deeper understanding to the mechanism of IPC.
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Skirnisdottir I, Bjersand K, Åkerud H, Seidal T. Napsin A as a marker of clear cell ovarian carcinoma. BMC Cancer 2013; 13:524. [PMID: 24191930 PMCID: PMC4228360 DOI: 10.1186/1471-2407-13-524] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Accepted: 10/30/2013] [Indexed: 01/03/2023] Open
Abstract
BACKGROUND Clear cell carcinomas are aggressive tumors with a distinct biologic behaviour. In a genome-wide screening for genes involved in chemo-resistance, NAPA was over-expressed in cisplatin-resistant cells. The NAPA (protein) Napsin A was described to promote resistance to cisplatin by degradation of the tumor suppressor p53. METHODS Totally 131 patients were included in this study all in FIGO-stages I-II; 16 were clear cell tumors which were compared with 40 Type I tumors and 75 type II tumors according to the markers Napsin A, p21, p53 and p27 and some clinical features. For detection of the markers tissue microarrays and immunohistochemistry were used. RESULTS Positivity for Napsin A was detected in 12 (80%) out of the 15 clear cell tumors available for analysis compared with 3 (4%) out of the Type I and II tumors in one group (p<0.001). Differences in p21 status, p53 status, and p21+p53- status were striking when clear cell tumors were compared with Type I, Type II, and Type I and II tumors in one group, respectively. The p21+p53-status was associated to positive staining of Napsin A (p=0.0015) and clear cell morphology (p=0.0003). In two separate multivariate logistic regression analyses with Napsin A as endpoint both clear cell carcinoma with OR=153 (95% C.I. 21-1107); (p<001) and p21+p53- status with OR=5.36 (95% C.I. 1.6-17.5); (p=0.005) were independent predictive factors. ROC curves showed that AUC for Napsin A alone was 0.882, for p21+p53- it was 0.720 and for p21+p53-Napsin A+AUC was 0.795. Patients with clear cell tumors had lower (p=0.013) BMI than Type I patients and were younger (p=0.046) at diagnosis than Type II patients. Clear cell tumors had a higher frequency (p=0.039) of capsule rupture at surgery than Type I and II tumors. CONCLUSIONS Positivity of Napsin A in an epithelial ovarian tumor might strengthen the morphological diagnosis of clear cell ovarian carcinoma in the process of differential diagnosis between clear cell ovarian tumors and other histological subtypes.
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Affiliation(s)
| | - Kathrine Bjersand
- Department of Women’s and Children’s Health, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Helena Åkerud
- Department of Women’s and Children’s Health, Uppsala University, SE-751 85 Uppsala, Sweden
| | - Tomas Seidal
- Department of Pathology, Halmstad Medical Center Hospital, Halmstad, Sweden
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Fåhraeus R, Olivares-Illana V. MDM2's social network. Oncogene 2013; 33:4365-76. [PMID: 24096477 DOI: 10.1038/onc.2013.410] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 08/17/2013] [Accepted: 08/17/2013] [Indexed: 12/22/2022]
Abstract
MDM2 is considered a hub protein due to its capacity to interact with a large number of different partners of which p53 is most well described. MDM2 is an E3 ubiquitin ligase, and many, but not all, of its interactions relate directly to this activity, such as substrates, adaptors or bridges, promoters, inhibitors or complementary factors. Some interactions serve regulatory functions that in response to cellular stresses control the localisation and functions of MDM2 including protein kinases, ribosomal proteins and proteases. Moreover, interactions with nucleotides serve other functions such as mRNA to regulate protein synthesis and DNA to control transcription. To perform such a pleiotropic panorama of different functions, MDM2 is subjected to a multitude of post-translational modifications and is expressed in different isoforms. The large and diverse interactome is made possible due to the plasticity of MDM2 and in this review we have listed the MDM2 interactions until now and we will discuss how this multifaceted protein can interact with such a variety of substrates to provide a key intermediary role in different signalling pathways.
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Affiliation(s)
- R Fåhraeus
- Cibles Therapeutiques, Equipe Labellisée Ligue Contre le Cancer, INSERM Unité 940, Institut de Génétique Moléculaire, Université Paris 7, Hôpital St Louis, 27 rue Juliette Dodu, Paris, France
| | - V Olivares-Illana
- Instituto de Física, Universidad Autónoma de San Luis Potosí, Av. Manuel Nava, Zona Universitaria, San Luis Potosí, México
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Dinh PX, Das A, Franco R, Pattnaik AK. Heterogeneous nuclear ribonucleoprotein K supports vesicular stomatitis virus replication by regulating cell survival and cellular gene expression. J Virol 2013; 87:10059-69. [PMID: 23843646 PMCID: PMC3754001 DOI: 10.1128/jvi.01257-13] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2013] [Accepted: 06/30/2013] [Indexed: 11/20/2022] Open
Abstract
The heterogeneous nuclear ribonucleoprotein K (hnRNP K) is a member of the family of hnRNPs and was recently shown in a genome-wide small interfering RNA (siRNA) screen to support vesicular stomatitis virus (VSV) growth. To decipher the role of hnRNP K in VSV infection, we conducted studies which suggest that the protein is required for VSV spreading. Virus binding to cells, entry, and nucleocapsid uncoating steps were not adversely affected in the absence of hnRNP K, whereas viral genome transcription and replication were reduced slightly. These results indicate that hnRNP K is likely involved in virus assembly and/or release from infected cells. Further studies showed that hnRNP K suppresses apoptosis of virus-infected cells, resulting in increased cell survival during VSV infection. The increased survival of the infected cells was found to be due to the suppression of proapoptotic proteins such as Bcl-XS and Bik in a cell-type-dependent manner. Additionally, depletion of hnRNP K resulted in not only significantly increased levels of T-cell-restricted intracellular antigen 1 (TIA1) but also switching of the expression of the two isoforms of the protein (TIA1a and TIA1b), both of which inhibited VSV replication. hnRNP K was also found to support expression of several cellular proteins known to be required for VSV infection. Overall, our studies demonstrate hnRNP K to be a multifunctional protein that supports VSV infection via its role(s) in suppressing apoptosis of infected cells, inhibiting the expression of antiviral proteins, and maintaining the expression of proteins required for the virus.
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Affiliation(s)
- Phat X. Dinh
- School of Veterinary Medicine and Biomedical Sciences
- Nebraska Center for Virology, University of Nebraska—Lincoln, Lincoln, Nebraska, USA
| | - Anshuman Das
- School of Veterinary Medicine and Biomedical Sciences
- Nebraska Center for Virology, University of Nebraska—Lincoln, Lincoln, Nebraska, USA
| | | | - Asit K. Pattnaik
- School of Veterinary Medicine and Biomedical Sciences
- Nebraska Center for Virology, University of Nebraska—Lincoln, Lincoln, Nebraska, USA
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