1
|
Li X, Jin H, Lv Y, Liu C, Luo X, Liu J, Zhang Q, Yu Y, Zhao Z. Analysis of microRNA expression profiles during the differentiation of chicken embryonic stem cells into male germ cells. Anim Biotechnol 2023; 34:1120-1131. [PMID: 35020556 DOI: 10.1080/10495398.2021.2013858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
The differentiation of embryonic stem cells (ESCs) into germ cells in vitro could have very promising applications for infertility treatment and could provide an excellent model for uncovering the molecular mechanisms of germline generation. This study aimed to investigate the differentially expressed miRNAs (DEMs) during the differentiation of chicken ESCs (cESCs) into male germ cells and to establish a profile of the DEMs. Cells before and after induction were subjected to miRNA sequencing (miRNA-seq). A total of 113 DEMs were obtained, including 61 upregulated and 52 downregulated DEMs. GO and KEGG enrichment analyses showed that the target genes were enriched mainly in the MAPK signaling pathway, HTLV infection signaling pathway, cell adhesion molecule (CAM)-related pathways, viral myocarditis, Wnt signaling pathway, ABC transporters, TGF-β signaling pathways, Notch signaling pathways and insulin signaling pathway. The target genes of the miRNAs were related to cell binding, cell parts and biological regulatory processes. Six DEMs, let-7k-5p, miR-132c-5p, miR-193a-5p, miR-202-5p, miR-383-5p and miR-6553-3p, were assessed by qRT-PCR, and the results were consistent with the results of miRNA-seq. Based on qRT-PCR and western blot verification, miR-383-5p and its putative target gene STRN3 were selected to construct an STRN3 3'-UTR dual-luciferase gene reporter vector and its mutant vector. The double luciferase reporter activity of the cotransfected STRN3-WT + miR-383-5p mimics group was significantly lower (by approximately 46%) than that of the other five groups (p < 0.01). There was no significant difference in luciferase activity among the other 5 groups. This study establishes a DEM profile during the process of cESC differentiation into male germ cells; illustrates the mechanisms by which miRNAs regulate target genes; provides a theoretical basis for further research on the mechanisms of the formation and regulation of male germ cells; and provides an important strategy for gene editing, animal genetic resource protection and transgenic animal production.
Collapse
Affiliation(s)
- Xin Li
- Institute of Animal Biotechnology, Jilin Academy of Agricultural Sciences, Gong Zhu Ling, China
| | - Haiguo Jin
- Institute of Animal Biotechnology, Jilin Academy of Agricultural Sciences, Gong Zhu Ling, China
| | - Yang Lv
- College of Animal Science and Technology, Northwest A&F University, Yangling, China
| | - Chen Liu
- Institute of Animal Husbandry and Veterinary Medicine, Jilin Academy of Agricultural Sciences, Gong Zhu Ling, China
| | - Xiaotong Luo
- Agricultural College, Yanbian University, Yanji, China
| | - Jianqiang Liu
- Institute of Animal Biotechnology, Jilin Academy of Agricultural Sciences, Gong Zhu Ling, China
| | - Qi Zhang
- Institute of Animal Biotechnology, Jilin Academy of Agricultural Sciences, Gong Zhu Ling, China
| | - Yongsheng Yu
- Institute of Animal Biotechnology, Jilin Academy of Agricultural Sciences, Gong Zhu Ling, China
| | - Zhongli Zhao
- Institute of Animal Husbandry and Veterinary Medicine, Jilin Academy of Agricultural Sciences, Gong Zhu Ling, China
| |
Collapse
|
2
|
Tanti GK, Pandey P, Shreya S, Jain BP. Striatin family proteins: The neglected scaffolds. BIOCHIMICA ET BIOPHYSICA ACTA. MOLECULAR CELL RESEARCH 2023; 1870:119430. [PMID: 36638846 DOI: 10.1016/j.bbamcr.2023.119430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2022] [Revised: 12/19/2022] [Accepted: 12/31/2022] [Indexed: 01/12/2023]
Abstract
The Striatin family of proteins constitutes Striatin, SG2NA, and Zinedin. Members of this family of proteins act as a signaling scaffold due to the presence of multiple protein-protein interaction domains. At least two members of this family, namely Zinedin and SG2NA, have a proven role in cancer cell proliferation. SG2NA, the second member of this family, undergoes alternative splicing and gives rise to several isoforms which are differentially regulated in a tissue-dependent manner. SG2NA evolved earlier than the other two members of the family, and SG2NA undergoes not only alternative splicing but also other posttranscriptional gene regulation. Striatin also undergoes alternative splicing, and as a result, it gives rise to multiple isoforms. It has been shown that this family of proteins plays a significant role in estrogen signaling, neuroprotection, cancer as well as in cell cycle regulation. Members of the striatin family form a complex network of signaling hubs with different kinases and phosphatases, and other signaling proteins named STRIPAK. Here, in the present manuscript, we thoroughly reviewed the findings on striatin family members to elaborate on the overall structural and functional idea of this family of proteins. We also commented on the involvement of these proteins in STRIPAK complexes and their functional relevance.
Collapse
Affiliation(s)
- Goutam Kumar Tanti
- Department of Neurology, School of Medicine, Technical University of Munich, Germany.
| | - Prachi Pandey
- National Institute of Plant Genome Research, New Delhi, India
| | - Smriti Shreya
- Department of Zoology, Mahatma Gandhi Central University, Motihari, Bihar, India
| | - Buddhi Prakash Jain
- Department of Zoology, Mahatma Gandhi Central University, Motihari, Bihar, India.
| |
Collapse
|
3
|
Guo CL. Self-Sustained Regulation or Self-Perpetuating Dysregulation: ROS-dependent HIF-YAP-Notch Signaling as a Double-Edged Sword on Stem Cell Physiology and Tumorigenesis. Front Cell Dev Biol 2022; 10:862791. [PMID: 35774228 PMCID: PMC9237464 DOI: 10.3389/fcell.2022.862791] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/29/2022] [Indexed: 12/19/2022] Open
Abstract
Organ development, homeostasis, and repair often rely on bidirectional, self-organized cell-niche interactions, through which cells select cell fate, such as stem cell self-renewal and differentiation. The niche contains multiplexed chemical and mechanical factors. How cells interpret niche structural information such as the 3D topology of organs and integrate with multiplexed mechano-chemical signals is an open and active research field. Among all the niche factors, reactive oxygen species (ROS) have recently gained growing interest. Once considered harmful, ROS are now recognized as an important niche factor in the regulation of tissue mechanics and topology through, for example, the HIF-YAP-Notch signaling pathways. These pathways are not only involved in the regulation of stem cell physiology but also associated with inflammation, neurological disorder, aging, tumorigenesis, and the regulation of the immune checkpoint molecule PD-L1. Positive feedback circuits have been identified in the interplay of ROS and HIF-YAP-Notch signaling, leading to the possibility that under aberrant conditions, self-organized, ROS-dependent physiological regulations can be switched to self-perpetuating dysregulation, making ROS a double-edged sword at the interface of stem cell physiology and tumorigenesis. In this review, we discuss the recent findings on how ROS and tissue mechanics affect YAP-HIF-Notch-PD-L1 signaling, hoping that the knowledge can be used to design strategies for stem cell-based and ROS-targeting therapy and tissue engineering.
Collapse
Affiliation(s)
- Chin-Lin Guo
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| |
Collapse
|
4
|
The profile of expression of the scaffold protein SG2NA(s) differs between cancer types and its interactome in normal vis-a-vis breast tumor tissues suggests its wide roles in regulating multiple cellular pathways. Mol Cell Biochem 2022; 477:1653-1668. [PMID: 35230605 DOI: 10.1007/s11010-022-04401-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 02/18/2022] [Indexed: 10/19/2022]
Abstract
Striatin and SG2NA are scaffold proteins that form signaling complexes called STRIPAK. It has been associated with developmental abnormalities, cancer, and several other diseases. Our earlier studies have shown that SG2NA forms a complex with the cancer-associated protein DJ-1 and the signaling kinase Akt, promoting cancer cell survival. In the present study, we used bioinformatics analyses to confirm the existence of two isoforms of human SG2NA, i.e., 78 and 87 kDas. In addition, several smaller isoforms like 35 kDa were also seen in western blot analyses of human cell lysates. The expression of these isoforms varies between different cancer cell lines of human origin. Also, the protein levels do not corroborate with its transcript levels, suggesting a complex regulation of its expression. In breast tumor tissues, the expression of the 35 and 78 kDa isoforms was higher as compared to the adjacent normal tissues, while the 87 kDa isoform was found in the breast tumor tissues only. With the progression of stages of breast cancer, while the expression of 78 kDa isoform decreased, 87 kDa became undetectable. In co-immunoprecipitation assays, the profile of the SG2NA interactome in breast tumors vis-à-vis adjacent normal breast tissues showed hundreds of common proteins. Also, some proteins were interacted with SG2NA in breast tumor tissues only. We conclude that SG2NA is involved in diverse cellular pathways and has roles in cellular reprogramming during tumorigenesis of the breast.
Collapse
|
5
|
Sandal P, Jong CJ, Merrill RA, Song J, Strack S. Protein phosphatase 2A - structure, function and role in neurodevelopmental disorders. J Cell Sci 2021; 134:270819. [PMID: 34228795 DOI: 10.1242/jcs.248187] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Neurodevelopmental disorders (NDDs), including intellectual disability (ID), autism and schizophrenia, have high socioeconomic impact, yet poorly understood etiologies. A recent surge of large-scale genome or exome sequencing studies has identified a multitude of mostly de novo mutations in subunits of the protein phosphatase 2A (PP2A) holoenzyme that are strongly associated with NDDs. PP2A is responsible for at least 50% of total Ser/Thr dephosphorylation in most cell types and is predominantly found as trimeric holoenzymes composed of catalytic (C), scaffolding (A) and variable regulatory (B) subunits. PP2A can exist in nearly 100 different subunit combinations in mammalian cells, dictating distinct localizations, substrates and regulatory mechanisms. PP2A is well established as a regulator of cell division, growth, and differentiation, and the roles of PP2A in cancer and various neurodegenerative disorders, such as Alzheimer's disease, have been reviewed in detail. This Review summarizes and discusses recent reports on NDDs associated with mutations of PP2A subunits and PP2A-associated proteins. We also discuss the potential impact of these mutations on the structure and function of the PP2A holoenzymes and the etiology of NDDs.
Collapse
Affiliation(s)
- Priyanka Sandal
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Chian Ju Jong
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Ronald A Merrill
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Jianing Song
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| | - Stefan Strack
- Department of Neuroscience and Pharmacology, and Iowa Neuroscience Institute, University of Iowa, Iowa City, Iowa 52242, USA
| |
Collapse
|
6
|
Gao RL, Liu LK, Guo LM, Wang KJ, Liu HP. CqPP2A inhibits white spot syndrome virus infection by up-regulating antimicrobial substances expression in red claw crayfish Cherax quadricarinatus. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 116:103913. [PMID: 33137394 DOI: 10.1016/j.dci.2020.103913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 06/11/2023]
Abstract
Protein phosphatase 2A (PP2A) is an important serine/threonine phosphatase, a highly conserved enzyme widely expressed in eukaryotic cells, which accounts for a majority of the serine/threonine phosphatase activity in cells implicated in regulation of immune signaling pathways and antiviral response. However, most of studies about PP2A have been conducted in mammals but few in crustaceans. In this study, two subunits of PP2A (named as CqPP2Ab and CqPP2Ac) were characterized to be involved in white spot syndrome virus (WSSV) infection in the haematopoietic tissue (Hpt) cells from red claw crayfish Cherax quadricarinatus. The open reading frame (ORF) of CqPP2Ab was 1341 bp encoding 446 amino acids with seven WD40 domains, and the ORF of CqPP2Ac was 930 bp encoding 309 amino acids with a PP2Ac domain. Tissue distribution analysis showed that the mRNA transcript of CqPP2Ab and CqPP2Ac were both widely expressed in all the tested tissues with the highest expression in hemocyte, followed by high expression in Hpt. The gene expressions of CqPP2Ab and CqPP2Ac were both significantly down-regulated at 6 h post WSSV infection (6 hpi) in Hpt cells. Importantly, the expression of viral immediate early gene IE1 and late viral gene envelope protein VP28 were both significantly increased post WSSV infection after gene silencing of CqPP2Ab or CqPP2Ac in Hpt cells, suggesting that CqPP2Ab and CqPP2Ac could inhibit WSSV infection in Hpt cells, probably by increasing the antimicrobial substances expression in consideration to the significantly reduced expression of anti-lipopolysaccharide factor, crustin, and lysozyme after gene silencing of CqPP2Ab or CqPP2Ac, respectively. These findings provide a new light on the mechanism of WSSV infection and the antiviral response in crustaceans.
Collapse
Affiliation(s)
- Rui-Lin Gao
- State Key Laboratory of Marine Environmental Science, State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Ling-Ke Liu
- State Key Laboratory of Marine Environmental Science, State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Li-Mei Guo
- State Key Laboratory of Marine Environmental Science, State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Ke-Jian Wang
- State Key Laboratory of Marine Environmental Science, State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, Fujian, China
| | - Hai-Peng Liu
- State Key Laboratory of Marine Environmental Science, State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, Fujian, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology, Qingdao, China.
| |
Collapse
|
7
|
Cryo-EM structure of the Hippo signaling integrator human STRIPAK. Nat Struct Mol Biol 2021; 28:290-299. [PMID: 33633399 PMCID: PMC8315899 DOI: 10.1038/s41594-021-00564-y] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/20/2021] [Indexed: 01/31/2023]
Abstract
The striatin-interacting phosphatase and kinase (STRIPAK) complex is a large, multisubunit protein phosphatase 2A (PP2A) assembly that integrates diverse cellular signals in the Hippo pathway to regulate cell proliferation and survival. The architecture and assembly mechanism of this critical complex are poorly understood. Using cryo-EM, we determine the structure of the human STRIPAK core comprising PP2AA, PP2AC, STRN3, STRIP1, and MOB4 at 3.2-Å resolution. Unlike the canonical trimeric PP2A holoenzyme, STRIPAK contains four copies of STRN3 and one copy of each the PP2AA-C heterodimer, STRIP1, and MOB4. The STRN3 coiled-coil domains form an elongated homotetrameric scaffold that links the complex together. An inositol hexakisphosphate (IP6) is identified as a structural cofactor of STRIP1. Mutations of key residues at subunit interfaces disrupt the integrity of STRIPAK, causing aberrant Hippo pathway activation. Thus, STRIPAK is established as a noncanonical PP2A complex with four copies of regulatory STRN3 for enhanced signal integration.
Collapse
|
8
|
Nadar-Ponniah PT, Taiber S, Caspi M, Koffler-Brill T, Dror AA, Siman-Tov R, Rubinstein M, Padmanabhan K, Luxenburg C, Lang RA, Avraham KB, Rosin-Arbesfeld R. Striatin Is Required for Hearing and Affects Inner Hair Cells and Ribbon Synapses. Front Cell Dev Biol 2020; 8:615. [PMID: 32766247 PMCID: PMC7381154 DOI: 10.3389/fcell.2020.00615] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Accepted: 06/22/2020] [Indexed: 12/22/2022] Open
Abstract
Striatin, a subunit of the serine/threonine phosphatase PP2A, is a core member of the conserved striatin-interacting phosphatase and kinase (STRIPAK) complexes. The protein is expressed in the cell junctions between epithelial cells, which play a role in maintaining cell-cell adhesion. Since the cell junctions are crucial for the function of the mammalian inner ear, we examined the localization and function of striatin in the mouse cochlea. Our results show that in neonatal mice, striatin is specifically expressed in the cell-cell junctions of the inner hair cells, the receptor cells in the mammalian cochlea. Auditory brainstem response measurements of striatin-deficient mice indicated a progressive, high-frequency hearing loss, suggesting that striatin is essential for normal hearing. Moreover, scanning electron micrographs of the organ of Corti revealed a moderate degeneration of the outer hair cells in the middle and basal regions, concordant with the high-frequency hearing loss. Additionally, striatin-deficient mice show aberrant ribbon synapse maturation. Loss of the outer hair cells, combined with the aberrant ribbon synapse distribution, may lead to the observed auditory impairment. Together, these results suggest a novel function for striatin in the mammalian auditory system.
Collapse
Affiliation(s)
- Prathamesh T. Nadar-Ponniah
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shahar Taiber
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Michal Caspi
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tal Koffler-Brill
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Amiel A. Dror
- Department of Otolaryngology, Head and Neck Surgery, Galilee Medical Center, Nahariya, Israel
- Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ronen Siman-Tov
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Moran Rubinstein
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
- Goldschleger Eye Research Institute, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Krishnanand Padmanabhan
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chen Luxenburg
- Department of Cell and Developmental Biology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Richard A. Lang
- Visual Systems Group, Abrahamson Pediatric Eye Institute, Division of Pediatric Ophthalmology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
| | - Karen B. Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
9
|
Neal SJ, Zhou Q, Pignoni F. STRIPAK-PP2A regulates Hippo-Yorkie signaling to suppress retinal fate in the Drosophila eye disc peripodial epithelium. J Cell Sci 2020; 133:jcs237834. [PMID: 32184260 PMCID: PMC7272332 DOI: 10.1242/jcs.237834] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Accepted: 03/09/2020] [Indexed: 12/30/2022] Open
Abstract
The specification of organs, tissues and cell types results from cell fate restrictions enacted by nuclear transcription factors under the control of conserved signaling pathways. The progenitor epithelium of the Drosophila compound eye, the eye imaginal disc, is a premier model for the study of such processes. Early in development, apposing cells of the eye disc are established as either retinal progenitors or support cells of the peripodial epithelium (PE), in a process whose genetic and mechanistic determinants are poorly understood. We have identified protein phosphatase 2A (PP2A), and specifically a STRIPAK-PP2A complex that includes the scaffolding and substrate-specificity components Cka, Strip and SLMAP, as a critical player in the retina-PE fate choice. We show that these factors suppress ectopic retina formation in the presumptive PE and do so via the Hippo signaling axis. STRIPAK-PP2A negatively regulates Hippo kinase, and consequently its substrate Warts, to release the transcriptional co-activator Yorkie into the nucleus. Thus, a modular higher-order PP2A complex refines the activity of this general phosphatase to act in a precise specification of cell fate.
Collapse
Affiliation(s)
- Scott J Neal
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
| | - Qingxiang Zhou
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
| | - Francesca Pignoni
- Department of Ophthalmology and Visual Sciences, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
- Department of Neuroscience and Physiology; Department of Biochemistry and Molecular Biology; Department of Cell and Developmental Biology, Upstate Medical University, 505 Irving Avenue, NRB 4610, Syracuse, NY 13210, USA
| |
Collapse
|
10
|
Schad EG, Petersen CP. STRIPAK Limits Stem Cell Differentiation of a WNT Signaling Center to Control Planarian Axis Scaling. Curr Biol 2020; 30:254-263.e2. [PMID: 31928872 DOI: 10.1016/j.cub.2019.11.068] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 10/14/2019] [Accepted: 11/22/2019] [Indexed: 01/26/2023]
Abstract
Regeneration involves regulating tissue proportionality across considerable size ranges through unknown mechanisms. In planarians, which scale reversibly over 40× through regeneration, we identify the Striatin-interacting phosphatase and kinase (STRIPAK) complex as a potent negative regulator of axis length. Inhibition of two proteins in the STRIPAK complex, mob4 and striatin, dramatically increased posterior length, through expansion of a posterior wnt1+ signaling center within midline muscle cells. wnt1 was required for tail expansion after mob4 inhibition and dynamically reestablishes proportionality after amputation in normal animals, indicating STRIPAK represses Wnt signaling for scaling. Regulation of wnt1 expansion was stem cell dependent, demonstrating that control of signaling-center production through stem cell differentiation underlies proportional growth in adult regenerative tissue.
Collapse
Affiliation(s)
- Erik G Schad
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Christian P Petersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA; Robert Lurie Comprehensive Cancer Center, Northwestern University, Evanston IL 60208, USA.
| |
Collapse
|
11
|
Kim JW, Berrios C, Kim M, Schade AE, Adelmant G, Yeerna H, Damato E, Iniguez AB, Florens L, Washburn MP, Stegmaier K, Gray NS, Tamayo P, Gjoerup O, Marto JA, DeCaprio J, Hahn WC. STRIPAK directs PP2A activity toward MAP4K4 to promote oncogenic transformation of human cells. eLife 2020; 9:53003. [PMID: 31913126 PMCID: PMC6984821 DOI: 10.7554/elife.53003] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2019] [Accepted: 01/07/2020] [Indexed: 12/13/2022] Open
Abstract
Alterations involving serine-threonine phosphatase PP2A subunits occur in a range of human cancers, and partial loss of PP2A function contributes to cell transformation. Displacement of regulatory B subunits by the SV40 Small T antigen (ST) or mutation/deletion of PP2A subunits alters the abundance and types of PP2A complexes in cells, leading to transformation. Here, we show that ST not only displaces common PP2A B subunits but also promotes A-C subunit interactions with alternative B subunits (B’’’, striatins) that are components of the Striatin-interacting phosphatase and kinase (STRIPAK) complex. We found that STRN4, a member of STRIPAK, is associated with ST and is required for ST-PP2A-induced cell transformation. ST recruitment of STRIPAK facilitates PP2A-mediated dephosphorylation of MAP4K4 and induces cell transformation through the activation of the Hippo pathway effector YAP1. These observations identify an unanticipated role of MAP4K4 in transformation and show that the STRIPAK complex regulates PP2A specificity and activity. Cells maintain a fine balance of signals that promote or counter cell growth and division. Two sets of enzymes – called kinases and phosphatases – contribute to this balance. In general, kinases “switch on” other proteins by tagging them with a phosphate molecule. This process is called phosphorylation. Phosphatases, on the other hand, dephosphorylate these proteins, switching them off. Cancer cells often have mutations that activate kinases to drive cancer growth. The same cells can have mutations that inactivate the phosphatases or reduce their abundance. The roles of phosphatases in cancer are still being studied. One major hurdle in this research is that it is not always clear how they recognize the proteins they dephosphorylate. Protein phosphatase 2A (or PP2A for short) is one of the phosphatases that is often mutated or deleted in human cancers. Even just reduced levels of PP2A can promote cancer. Kim, Berrios, Kim, Schade et al. used an experimental trick to decrease the phosphatase activity of PP2A in human cells growing in a dish. Biochemical analysis of these cells showed that, as expected, many proteins were now in their phosphorylated states. Unexpectedly, however, some proteins were dephosphorylated under these conditions. One of these proteins was called MAP4K4. In the case of MAP4K4, the dephosphorylated state contributes to the growth of the cancer cell. Kim et al. carried out further genetic and biochemical experiments to show that, in these cells, PP2A and MAP4K4 stay physically connected to one another. This connection was enabled by a group of proteins called the STRIPAK complex. The STRIPAK proteins directed the remaining PP2A towards MAP4K4. Low levels or activity of PP2A could, therefore, promote cancer in a different way. Taken together, PP2A is not a single phosphatase that always turns proteins off, but rather is a dual switch that turns off some proteins while turning on others. Future experiments will explore to what extent these findings also apply in tumors. Information about how mutations in PP2A affect human cancers could suggest new targets for cancer drugs.
Collapse
Affiliation(s)
- Jong Wook Kim
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Division of Medical Genetics, School of Medicine, University of California, San Diego, San Diego, United States.,Moores Cancer Center, University of California, San Diego, San Diego, United States
| | - Christian Berrios
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, United States
| | - Miju Kim
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Amy E Schade
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, United States
| | - Guillaume Adelmant
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, United States.,Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, United States.,Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, United States
| | - Huwate Yeerna
- Division of Medical Genetics, School of Medicine, University of California, San Diego, San Diego, United States
| | - Emily Damato
- Broad Institute of Harvard and MIT, Cambridge, United States
| | - Amanda Balboni Iniguez
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Laurence Florens
- Stowers Institute for Medical Research, Kansas City, United States
| | - Michael P Washburn
- Stowers Institute for Medical Research, Kansas City, United States.,Department of Pathology and Laboratory Medicine, University of Kansas Medical Center, Kansas City, United States
| | - Kim Stegmaier
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Pediatric Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Nathanael S Gray
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, United States
| | - Pablo Tamayo
- Division of Medical Genetics, School of Medicine, University of California, San Diego, San Diego, United States.,Moores Cancer Center, University of California, San Diego, San Diego, United States
| | - Ole Gjoerup
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States
| | - Jarrod A Marto
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Boston, United States.,Department of Pathology, Brigham and Women's Hospital and Harvard Medical School, Boston, United States.,Department of Oncologic Pathology, Dana-Farber Cancer Institute, Boston, United States
| | - James DeCaprio
- Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Program in Virology, Graduate School of Arts and Sciences, Harvard University, Cambridge, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, United States
| | - William C Hahn
- Broad Institute of Harvard and MIT, Cambridge, United States.,Department of Medical Oncology, Dana-Farber Cancer Institute, Boston, United States.,Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, United States
| |
Collapse
|
12
|
Chauhan P, Gupta R, Jain BP, Pandey S, Goswami SK. Subcellular dynamics of variants of SG2NA in NIH3T3 fibroblasts. Cell Biol Int 2019; 44:637-650. [PMID: 31773824 DOI: 10.1002/cbin.11264] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022]
Abstract
SG2NA, a WD40 repeat protein of the Striatin subfamily, has four splicing and one messenger RNA edit variants. It is fast emerging as a scaffold for multimeric signaling complexes with roles in tissue development and disease. The green fluorescent protein (GFP)-tagged variants of SG2NA were ectopically expressed in NIH3T3 cells and their modulation by serum and GSK3β-ERK signaling were monitored. The 87, 78, and 35 kDa variants showed a biphasic modulation by serum till 24 h but the 52 kDa variant remained largely unresponsive. Inhibition of phosphatases by okadaic acid increased the levels of the endogenous 78 kDa and the ectopically expressed GFP-tagged 87 and 78 kDa SG2NAs. Contrastingly, okadaic acid treatment reduced the level of GFP-tagged 35 kDa SG2NA, suggesting differential modes of their stability through phosphorylation-dephosphorylation. The inhibition of GSK3β by LiCl showed a gradual decrease in the levels of 78 kDa. In the case of the other variants viz, GFP-tagged 35, 52, and 87 kDa, inhibition of GSK3β caused an initial increase followed by a decrease with a subtle difference in kinetics and intensities. Similar results were also seen upon inhibition of GSK3β by small interfering RNA. All the variants showed an increase followed by a decrease upon inhibition of extracellular-signal-regulated-kinase (ERK). These variants are localized in the plasma membrane, endoplasmic reticulum, mitochondria, and the nucleus with different propensities and no discernable subcellular distribution was seen upon stimulation by serum and the inhibition of phosphatases, GSK3β, and ERK. Taken together, the variants of SG2NA are modulated by the kinase-phosphatase network in a similar but characteristic manner.
Collapse
Affiliation(s)
- Pooja Chauhan
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.,Department of Microbiology and Molecular Genetics, Hadassah Medical School, Institute of Medical Research Israel-Canada, The Hebrew University of Jerusalem, POB 12272, Jerusalem, 91120, Israel
| | - Richa Gupta
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
| | - Buddhi P Jain
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.,Department of Zoology, School of Life Sciences, Mahatma Gandhi Central University Bihar, Motihari, 845401, India
| | - Shweta Pandey
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.,APSGMNS Govt PG College, Kawardha, Chhatishgarh
| | - Shyamal K Goswami
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
| |
Collapse
|
13
|
Kück U, Radchenko D, Teichert I. STRIPAK, a highly conserved signaling complex, controls multiple eukaryotic cellular and developmental processes and is linked with human diseases. Biol Chem 2019; 400:1005-1022. [PMID: 31042639 DOI: 10.1515/hsz-2019-0173] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Accepted: 03/28/2019] [Indexed: 01/17/2023]
Abstract
The striatin-interacting phosphatases and kinases (STRIPAK) complex is evolutionary highly conserved and has been structurally and functionally described in diverse lower and higher eukaryotes. In recent years, this complex has been biochemically characterized better and further analyses in different model systems have shown that it is also involved in numerous cellular and developmental processes in eukaryotic organisms. Further recent results have shown that the STRIPAK complex functions as a macromolecular assembly communicating through physical interaction with other conserved signaling protein complexes to constitute larger dynamic protein networks. Here, we will provide a comprehensive and up-to-date overview of the architecture, function and regulation of the STRIPAK complex and discuss key issues and future perspectives, linked with human diseases, which may form the basis of further research endeavors in this area. In particular, the investigation of bi-directional interactions between STRIPAK and other signaling pathways should elucidate upstream regulators and downstream targets as fundamental parts of a complex cellular network.
Collapse
Affiliation(s)
- Ulrich Kück
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Daria Radchenko
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| | - Ines Teichert
- Allgemeine und Molekulare Botanik, Ruhr-Universität Bochum, Universitätsstr. 150, D-44780 Bochum, Germany
| |
Collapse
|
14
|
Mierke CT. The matrix environmental and cell mechanical properties regulate cell migration and contribute to the invasive phenotype of cancer cells. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2019; 82:064602. [PMID: 30947151 DOI: 10.1088/1361-6633/ab1628] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
The minimal structural unit of a solid tumor is a single cell or a cellular compartment such as the nucleus. A closer look inside the cells reveals that there are functional compartments or even structural domains determining the overall properties of a cell such as the mechanical phenotype. The mechanical interaction of these living cells leads to the complex organization such as compartments, tissues and organs of organisms including mammals. In contrast to passive non-living materials, living cells actively respond to the mechanical perturbations occurring in their microenvironment during diseases such as fibrosis and cancer. The transformation of single cancer cells in highly aggressive and hence malignant cancer cells during malignant cancer progression encompasses the basement membrane crossing, the invasion of connective tissue, the stroma microenvironments and transbarrier migration, which all require the immediate interaction of the aggressive and invasive cancer cells with the surrounding extracellular matrix environment including normal embedded neighboring cells. All these steps of the metastatic pathway seem to involve mechanical interactions between cancer cells and their microenvironment. The pathology of cancer due to a broad heterogeneity of cancer types is still not fully understood. Hence it is necessary to reveal the signaling pathways such as mechanotransduction pathways that seem to be commonly involved in the development and establishment of the metastatic and mechanical phenotype in several carcinoma cells. We still do not know whether there exist distinct metastatic genes regulating the progression of tumors. These metastatic genes may then be activated either during the progression of cancer by themselves on their migration path or in earlier stages of oncogenesis through activated oncogenes or inactivated tumor suppressor genes, both of which promote the metastatic phenotype. In more detail, the adhesion of cancer cells to their surrounding stroma induces the generation of intracellular contraction forces that deform their microenvironments by alignment of fibers. The amplitude of these forces can adapt to the mechanical properties of the microenvironment. Moreover, the adhesion strength of cancer cells seems to determine whether a cancer cell is able to migrate through connective tissue or across barriers such as the basement membrane or endothelial cell linings of blood or lymph vessels in order to metastasize. In turn, exposure of adherent cancer cells to physical forces, such as shear flow in vessels or compression forces around tumors, reinforces cell adhesion, regulates cell contractility and restructures the ordering of the local stroma matrix that leads subsequently to secretion of crosslinking proteins or matrix degrading enzymes. Hence invasive cancer cells alter the mechanical properties of their microenvironment. From a mechanobiological point-of-view, the recognized physical signals are transduced into biochemical signaling events that guide cellular responses such as cancer progression after the malignant transition of cancer cells from an epithelial and non-motile phenotype to a mesenchymal and motile (invasive) phenotype providing cellular motility. This transition can also be described as the physical attempt to relate this cancer cell transitional behavior to a T1 phase transition such as the jamming to unjamming transition. During the invasion of cancer cells, cell adaptation occurs to mechanical alterations of the local stroma, such as enhanced stroma upon fibrosis, and therefore we need to uncover underlying mechano-coupling and mechano-regulating functional processes that reinforce the invasion of cancer cells. Moreover, these mechanisms may also be responsible for the awakening of dormant residual cancer cells within the microenvironment. Physicists were initially tempted to consider the steps of the cancer metastasis cascade as single events caused by a single mechanical alteration of the overall properties of the cancer cell. However, this general and simple view has been challenged by the finding that several mechanical properties of cancer cells and their microenvironment influence each other and continuously contribute to tumor growth and cancer progression. In addition, basement membrane crossing, cell invasion and transbarrier migration during cancer progression is explained in physical terms by applying physical principles on living cells regardless of their complexity and individual differences of cancer types. As a novel approach, the impact of the individual microenvironment surrounding cancer cells is also included. Moreover, new theories and models are still needed to understand why certain cancers are malignant and aggressive, while others stay still benign. However, due to the broad variety of cancer types, there may be various pathways solely suitable for specific cancer types and distinct steps in the process of cancer progression. In this review, physical concepts and hypotheses of cancer initiation and progression including cancer cell basement membrane crossing, invasion and transbarrier migration are presented and discussed from a biophysical point-of-view. In addition, the crosstalk between cancer cells and a chronically altered microenvironment, such as fibrosis, is discussed including the basic physical concepts of fibrosis and the cellular responses to mechanical stress caused by the mechanically altered microenvironment. Here, is highlighted how biophysical approaches, both experimentally and theoretically, have an impact on classical hallmarks of cancer and fibrosis and how they contribute to the understanding of the regulation of cancer and its progression by sensing and responding to the physical environmental properties through mechanotransduction processes. Finally, this review discusses various physical models of cell migration such as blebbing, nuclear piston, protrusive force and unjamming transition migration modes and how they contribute to cancer progression. Moreover, these cellular migration modes are influenced by microenvironmental perturbances such as fibrosis that can induce mechanical alterations in cancer cells, which in turn may impact the environment. Hence, the classical hallmarks of cancer need to be refined by including biomechanical properties of cells, cell clusters and tissues and their microenvironment to understand mechano-regulatory processes within cancer cells and the entire organism.
Collapse
|
15
|
Raman D, Pervaiz S. Redox inhibition of protein phosphatase PP2A: Potential implications in oncogenesis and its progression. Redox Biol 2019; 27:101105. [PMID: 30686777 PMCID: PMC6859563 DOI: 10.1016/j.redox.2019.101105] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 01/04/2019] [Accepted: 01/09/2019] [Indexed: 01/17/2023] Open
Abstract
Cellular processes are dictated by the active signaling of proteins relaying messages to regulate cell proliferation, apoptosis, signal transduction and cell communications. An intricate web of protein kinases and phosphatases are critical to the proper transmission of signals across such cascades. By governing 30–50% of all protein dephosphorylation in the cell, with prominent substrate proteins being key regulators of signaling cascades, the phosphatase PP2A has emerged as a celebrated player in various developmental and tumorigenic pathways, thereby posing as an attractive target for therapeutic intervention in various pathologies wherein its activity is deregulated. This review is mainly focused on refreshing our understanding of the structural and functional complexity that cocoons the PP2A phosphatase, and its expression in cancers. Additionally, we focus on its physiological regulation as well as into recent advents and strategies that have shown promise in countering the deregulation of the phosphatase through its targeted reactivation. Finally, we dwell upon one of the key regulators of PP2A in cancer cells-cellular redox status-its multifarious nature, and its integration into the reactome of PP2A, highlighting some of the significant impacts that ROS can inflict on the structural modifications and functional aspect of PP2A.
Collapse
Affiliation(s)
- Deepika Raman
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Shazib Pervaiz
- Department of Physiology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Medical Science Cluster Cancer Program, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; National University Cancer Institute, National University Health System, Singapore, Singapore; NUS Graduate School for Integrative Sciences and Engineering, National University of Singapore, Singapore.
| |
Collapse
|
16
|
Architecture, substructures, and dynamic assembly of STRIPAK complexes in Hippo signaling. Cell Discov 2019; 5:3. [PMID: 30622739 PMCID: PMC6323126 DOI: 10.1038/s41421-018-0077-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Revised: 12/08/2018] [Accepted: 12/10/2018] [Indexed: 01/24/2023] Open
Abstract
Striatin-interacting phosphatases and kinases (STRIPAKs) are evolutionarily conserved supramolecular complexes, which have been implicated in the Hippo signaling pathway. Yet the topological structure and dynamic assembly of STRIPAK complexes remain elusive. Here, we report the overall architecture and substructures of a Hippo kinase-containing STRIPAK complex. PP2Aa/c-bound STRN3 directly contacts the Hippo kinase MST2 and also controls the loading of MST2 via two “arms” in a phosphorylation-dependent manner, one arm being STRIP1 and the other SIKE1-SLMAP. A decreased cell density triggered the dissociation of the STRIP1 arm from STRIPAK, reflecting the dynamic assembly of the complex upon sensing upstream signals. Crystallographic studies defined at atomic resolution the interface between STRN3 and SIKE1, and that between SIKE1 and SLMAP. Disrupting the complex assembly abrogated the regulatory effect of STRIPAK towards Hippo signaling. Collectively, our study revealed a “two-arm” assembly of STRIPAK with context-dependent dynamics, offering a framework for further studies on Hippo signaling and biological processes involving MST kinases.
Collapse
|
17
|
Fowle H, Zhao Z, Graña X. PP2A holoenzymes, substrate specificity driving cellular functions and deregulation in cancer. Adv Cancer Res 2019; 144:55-93. [PMID: 31349904 PMCID: PMC9994639 DOI: 10.1016/bs.acr.2019.03.009] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
PP2A is a highly conserved eukaryotic serine/threonine protein phosphatase of the PPP family of phosphatases with fundamental cellular functions. In cells, PP2A targets specific subcellular locations and substrates by forming heterotrimeric holoenzymes, where a core dimer consisting of scaffold (A) and catalytic (C) subunits complexes with one of many B regulatory subunits. PP2A plays a key role in positively and negatively regulating a myriad of cellular processes, as it targets a very sizable fraction of the cellular substrates phosphorylated on Ser/Thr residues. This review focuses on insights made toward the understanding on how the subunit composition and structure of PP2A holoenzymes mediates substrate specificity, the role of substrate modulation in the signaling of cellular division, growth, and differentiation, and its deregulation in cancer.
Collapse
Affiliation(s)
- Holly Fowle
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Ziran Zhao
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States
| | - Xavier Graña
- Fels Institute for Cancer Research and Molecular Biology and Temple University Lewis Katz School of Medicine, Philadelphia, PA, United States.
| |
Collapse
|
18
|
Lahav-Ariel L, Caspi M, Nadar-Ponniah PT, Zelikson N, Hofmann I, Hanson KK, Franke WW, Sklan EH, Avraham KB, Rosin-Arbesfeld R. Striatin is a novel modulator of cell adhesion. FASEB J 2018; 33:4729-4740. [PMID: 30592649 DOI: 10.1096/fj.201801882r] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The adherens junctions (AJs) and tight junctions (TJs) provide critical adhesive contacts between neighboring epithelial cells and are crucial for epithelial adhesion, integrity, and barrier functions in a wide variety of tissues and organisms. The striatin protein family, which are part of the striatin interaction phosphatases and kinases complex, are multidomain scaffolding proteins that play important biologic roles. We have previously shown that striatin colocalizes with the tumor suppressor protein adenomatous polyposis coli in the TJs of epithelial cells. Here we show that striatin affects junction integrity and cell migration, probably through a mechanism that involves the adhesion molecule E-cadherin. Cells engaged in cell-cell adhesion expressed a high MW-modified form of striatin that forms stable associations with detergent-insoluble, membrane-bound cellular fractions. In addition, striatin has recently been suggested to be a target of the poly (ADP-ribose) polymerases Tankyrase 1, and we have found that striatin interacts with Tankyrase 1 and is subsequently poly-ADP-ribosylated. Taken together, our results suggest that striatin is a novel cell-cell junctional protein that functions to maintain correct cell adhesion and may have a role in establishing the relationship between AJs and TJs that is fundamental for epithelial cell-cell adhesion.-Lahav-Ariel, L., Caspi, M., Nadar-Ponniah, P. T., Zelikson, N., Hofmann, I., Hanson, K. K., Franke, W. W., Sklan, E. H., Avraham, K. B., Rosin-Arbesfeld, R. Striatin is a novel modulator of cell adhesion.
Collapse
Affiliation(s)
- Lital Lahav-Ariel
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Michal Caspi
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Prathamesh T Nadar-Ponniah
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.,Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Natalie Zelikson
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ilse Hofmann
- Division of Vascular Oncology and Metastasis, Center for Molecular Biology-German Cancer Research Center (DKFZ-ZMBH) Alliance, German Cancer Research Center, Heidelberg, Germany.,Department of Vascular Biology and Tumor Angiogenesis (CBTM), Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany
| | - Kirsten K Hanson
- Department of Biology and South Texas Center for Emerging Infectious Diseases, University of Texas at San Antonio, San Antonio, Texas, USA; and
| | - Werner W Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Ella H Sklan
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv, Israel
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
19
|
Baskaran R, Velmurugan BK. Protein phosphatase 2A as therapeutic targets in various disease models. Life Sci 2018; 210:40-46. [PMID: 30170071 DOI: 10.1016/j.lfs.2018.08.063] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 07/25/2018] [Accepted: 08/27/2018] [Indexed: 12/24/2022]
Abstract
There are a large number of signalling pathways responsible for transmitting information within the cell. Although cellular signalling is thought to be majorly governed by protein kinases 'cascade effects'; their antagonists protein phosphatases also play a crucial dual role in signal transduction. By dephosphorylating the proteins involved in signalling pathways, phosphatases may lead to their activation and sometimes they may terminate a signal generated by kinases activity. Due to counterbalancing the function of phosphorylation, the protein phosphatases are very important to signal transduction processes and thus the control of phosphatase activity is as significant as kinases, in the regulation of a plethora of cellular processes. In general, the protein phosphatases are comprised of a catalytic subunit with one or more regulatory and/or targeting subunits associated with it. The Protein Phosphatase 2A (PP2A), a member of serine/threonine phosphatases family, is ubiquitously expressed a remarkably conserved enzyme in the cell. Its catalytic activity has been highly regulated and may have enormous therapeutic potential which is still untapped. It has specificities for a number of substrates which witnessed its involvement in various signalling modules of cell cycle regulation, cell morphology and development. Thus it can be an appropriate target for studying different diseases associated with abnormal signal transduction pathways such as neurodegenerative diseases and malignancies. This review will focus on the structure and regulatory pathways of PP2A. The de-regulation of PP2A in some specific pathology such as Cancer, Heart diseases, Neurodegenerative disorders and Diabetes will also be touched upon.
Collapse
Affiliation(s)
- Rathinasamy Baskaran
- National Institute of Cancer Research, National Health Research Institutes, Zhunan, Miaoli County, Taiwan
| | - Bharath Kumar Velmurugan
- Toxicology and Biomedicine Research Group, Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
| |
Collapse
|
20
|
Zheng S, Sun P, Liu H, Li R, Long L, Xu Y, Chen S, Xu J. 17β-estradiol upregulates striatin protein levels via Akt pathway in human umbilical vein endothelial cells. PLoS One 2018; 13:e0202500. [PMID: 30138337 PMCID: PMC6107185 DOI: 10.1371/journal.pone.0202500] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Accepted: 08/04/2018] [Indexed: 11/19/2022] Open
Abstract
17β-estradiol (E2) has been shown to have beneficial effects on the cardiovascular system. We previously demonstrated that E2 increases striatin levels and inhibits migration in vascular smooth muscle cells. The objective of the present study was to investigate the effects of E2 on the regulation of striatin expression in human umbilical vein endothelial cells (HUVECs). We demonstrated that E2 increased striatin protein expression in a dose- and time-dependent manner in HUVECs. Pretreatment with ICI 182780 or the phosphatidylinositol-3 kinase inhibitor, wortmannin, abolished E2-mediated upregulation of striatin protein expression. Treatment with E2 resulted in Akt phosphorylation in a time-dependent manner. Moreover, silencing striatin significantly inhibited HUVEC migration, while striatin overexpression significantly promoted HUVEC migration. Finally, E2 enhanced HUVEC migration, which was inhibited by silencing striatin. In conclusion, our results demonstrated that E2-mediated upregulation of striatin promotes cell migration in HUVECs.
Collapse
Affiliation(s)
- Shuhui Zheng
- Research Center of Translational Medicine, the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Peng Sun
- Department of Pathology, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative innovation Center for Cancer Medicine, Guangzhou, China
| | - Haimei Liu
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Runmei Li
- School of Chinese Pharmaceutical Science, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Lingli Long
- Research Center of Translational Medicine, the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Yuxia Xu
- Research Center of Translational Medicine, the First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong Province, China
| | - Suiqing Chen
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Jinwen Xu
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
- * E-mail:
| |
Collapse
|
21
|
Soni S, Jain BP, Gupta R, Dharavath S, Kar K, Komath SS, Goswami SK. Biophysical Characterization of SG2NA Variants and their Interaction with DJ-1 and Calmodulin in vitro. Cell Biochem Biophys 2018; 76:451-461. [PMID: 30132185 DOI: 10.1007/s12013-018-0854-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Accepted: 08/13/2018] [Indexed: 01/11/2023]
Abstract
SG2NA was first discovered as nuclear autoantigen in lung and bladder cancer patient. It was named SG2NA as its expression increases during S to G2 phase of cell cycle. SG2NA/Striatin3 was classified as a member of Striatin family along with Straitin and Zinedin due to its structural and functional relatedness. At the molecular level, SG2NA is characterized by the presence of multiple protein-protein interaction domains viz., a caveolin binding motif, a coiled coil structure, Ca2+-calmodulin binding domain and a large WD-40 repeat domain in the same order from amino to the carboxyl termini. Analysis of secondary structures of 87 and 78 kDa SG2NA isoforms showed characteristic combinations of α-helix, β-structure, β-turns and random coil; suggesting of effective refolding after denaturation. This study for the first time establishes the structural differences between the two prevalent isoforms of SG2NA. Recently we observed that DJ-1 interacts with variants of SG2NA both in vitro and in vivo. The SG2NA isoforms purified from inclusion bodies showed the different secondary structure conformations, stability and interaction pattern for their interacting partners (DJ-1 and calmodulin) which imparts functional diversity of SG2NA. The SG2NA isoforms showed significant differential binding affinity to DJ-1 and Calmodulin.
Collapse
Affiliation(s)
- Sangeeta Soni
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,Department of Genetics, Barkatullah University, Bhopal, 462022, India
| | - Buddhi Prakash Jain
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.,Department of Zoology, School of Life Sciences, Mahatma Gandhi Central University Bihar, Motihari, 845401, India
| | - Richa Gupta
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sudhaker Dharavath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Karunakar Kar
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India
| | - Sneha Sudha Komath
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
| | - Shyamal K Goswami
- School of Life Sciences, Jawaharlal Nehru University, New Delhi, 110067, India.
| |
Collapse
|
22
|
Kim MS, Zhang H, Yan H, Yoon BJ, Shim WB. Characterizing co-expression networks underpinning maize stalk rot virulence in Fusarium verticillioides through computational subnetwork module analyses. Sci Rep 2018; 8:8310. [PMID: 29844502 PMCID: PMC5974142 DOI: 10.1038/s41598-018-26505-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2017] [Accepted: 05/11/2018] [Indexed: 11/15/2022] Open
Abstract
Fusarium verticillioides is recognized as an important stalk rot pathogen of maize worldwide, but our knowledge of genetic mechanisms underpinning this pathosystem is limited. Previously, we identified a striatin-like protein Fsr1 that plays an important role in stalk rot. To further characterize transcriptome networks downstream of Fsr1, we performed next-generation sequencing (NGS) to investigate relative read abundance and also to infer co-expression networks utilizing the preprocessed expression data through partial correlation. We used a probabilistic pathway activity inference strategy to identify functional subnetwork modules likely involved in virulence. Each subnetwork modules consisted of multiple correlated genes with coordinated expression patterns, but the collective activation levels were significantly different in F. verticillioides wild type versus fsr1 mutant. We also identified putative hub genes from predicted subnetworks for functional validation and network robustness studies through mutagenesis, virulence and qPCR assays. Our results suggest that these genes are important virulence genes that regulate the expression of closely correlated genes, demonstrating that these are important hubs of their respective subnetworks. Lastly, we used key F. verticillioides virulence genes to computationally predict a subnetwork of maize genes that potentially respond to fungal genes by applying cointegration-correlation-expression strategy.
Collapse
Affiliation(s)
- Man S Kim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States.,Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, 77843, United States
| | - Huan Zhang
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States
| | - Huijuan Yan
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States
| | - Byung-Jun Yoon
- Department of Electrical and Computer Engineering, Texas A&M University, College Station, TX, 77843, United States
| | - Won Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station, TX, 77843, United States.
| |
Collapse
|
23
|
Li D, Musante V, Zhou W, Picciotto MR, Nairn AC. Striatin-1 is a B subunit of protein phosphatase PP2A that regulates dendritic arborization and spine development in striatal neurons. J Biol Chem 2018; 293:11179-11194. [PMID: 29802198 DOI: 10.1074/jbc.ra117.001519] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 05/06/2018] [Indexed: 01/09/2023] Open
Abstract
Striatin-1, a subunit of the serine/threonine phosphatase PP2A, is preferentially expressed in neurons in the striatum. As a member of the striatin family of B subunits, striatin-1 is a core component together with PP2A of a multiprotein complex called STRIPAK, the striatin-interacting phosphatase and kinase complex. Little is known about the function of striatin-1 or the STRIPAK complex in the mammalian striatum. Here, we identify a selective role for striatin-1 in striatal neuron maturation. Using a small hairpin RNA (shRNA) knockdown approach in primary striatal neuronal cultures, we determined that reduced expression of striatin-1 results in increased dendritic complexity and an increased density of dendritic spines, classified as stubby spines. The dendritic phenotype was rescued by co-expression of a striatin-1 mutant construct insensitive to the knockdown shRNA but was not rescued by co-expression of PP2A- or Mob3-binding deficient striatin-1 constructs. Reduction of striatin-1 did not result in deficits in neuronal connectivity in this knockdown model, as we observed no abnormalities in synapse formation or in spontaneous excitatory postsynaptic currents. Thus, this study suggests that striatin-1 is a regulator of neuronal development in striatal neurons.
Collapse
Affiliation(s)
- Daniel Li
- From the Department of Psychiatry, Yale University, New Haven, Connecticut 06520
| | - Veronica Musante
- From the Department of Psychiatry, Yale University, New Haven, Connecticut 06520
| | - Wenliang Zhou
- From the Department of Psychiatry, Yale University, New Haven, Connecticut 06520
| | - Marina R Picciotto
- From the Department of Psychiatry, Yale University, New Haven, Connecticut 06520
| | - Angus C Nairn
- From the Department of Psychiatry, Yale University, New Haven, Connecticut 06520
| |
Collapse
|
24
|
Zhang H, Mukherjee M, Kim J, Yu W, Shim W. Fsr1, a striatin homologue, forms an endomembrane-associated complex that regulates virulence in the maize pathogen Fusarium verticillioides. MOLECULAR PLANT PATHOLOGY 2018; 19:812-826. [PMID: 28467007 PMCID: PMC6638083 DOI: 10.1111/mpp.12562] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2017] [Accepted: 04/06/2017] [Indexed: 05/09/2023]
Abstract
Fsr1, a homologue of mammalian striatin, containing multiple protein-binding domains and a coiled-coil (CC) domain, is critical for Fusarium verticillioides virulence. In mammals, striatin interacts with multiple proteins to form a STRIPAK (striatin-interacting phosphatase and kinase) complex that regulates a variety of developmental processes and cellular mechanisms. In this study, we identified the homologue of a key mammalian STRIPAK component STRIP1/2 (striatin-interacting proteins 1 and 2) in F. verticillioides, FvStp1, which interacts with Fsr1 in vivo. Gene deletion analysis indicates that FvStp1 is critical for F. verticillioides stalk rot virulence. In addition, we identified three proteins, designated FvCyp1, FvScp1 and FvSel1, which interact with the Fsr1 CC domain via a yeast two-hybrid screen. Importantly, FvCyp1, FvScp1 and FvSel1 co-localize to endomembrane structures, each having a preferred localization in the cell, and they are all required for F. verticillioides stalk rot virulence. Moreover, these proteins are necessary for the correct localization of Fsr1 to the endoplasmic reticulum (ER) and nuclear envelope. Thus, we identified several novel components in the STRIPAK complex that regulates F. verticillioides virulence, and propose that the correct organization and localization of Fsr1 are critical for STRIPAK complex function.
Collapse
Affiliation(s)
- Huan Zhang
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Mala Mukherjee
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Jung‐Eun Kim
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| | - Wenying Yu
- College of Life Science, Fujian Agricultural and Forestry UniversityFuzhou 350002China
| | - Won‐Bo Shim
- Department of Plant Pathology & MicrobiologyTexas A&M University, College StationTX 77843‐2132USA
| |
Collapse
|
25
|
STRIP1, a core component of STRIPAK complexes, is essential for normal mesoderm migration in the mouse embryo. Proc Natl Acad Sci U S A 2017; 114:E10928-E10936. [PMID: 29203676 PMCID: PMC5754794 DOI: 10.1073/pnas.1713535114] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Striatin-interacting phosphatases and kinases (STRIPAK) complexes can regulate the cytoskeleton and cell migration in cell lines, but their roles in vivo in mammals are not known. Here, we show that mouse embryos that lack striatin-interacting protein 1 (STRIP1), a core component of STRIPAK complexes, arrest at midgestation with striking morphological defects. Strip1 mutants lack a trunk, and both paraxial and axial mesoderm fail to elongate along the anterior–posterior body axis. Mesodermal cells from Strip1 mutants have defects in actin organization, focal adhesions, and cell migration that can account for the failure of normal mesoderm migration. The findings demonstrate that STRIPAK is a critical regulator of mammalian cell migration and is likely to have important roles in tumor progression as well as development. Regulated mesoderm migration is necessary for the proper morphogenesis and organ formation during embryonic development. Cell migration and its dependence on the cytoskeleton and signaling machines have been studied extensively in cultured cells; in contrast, remarkably little is known about the mechanisms that regulate mesoderm cell migration in vivo. Here, we report the identification and characterization of a mouse mutation in striatin-interacting protein 1 (Strip1) that disrupts migration of the mesoderm after the gastrulation epithelial-to-mesenchymal transition (EMT). STRIP1 is a core component of the biochemically defined mammalian striatin-interacting phosphatases and kinase (STRIPAK) complexes that appear to act through regulation of protein phosphatase 2A (PP2A), but their functions in mammals in vivo have not been examined. Strip1-null mutants arrest development at midgestation with profound disruptions in the organization of the mesoderm and its derivatives, including a complete failure of the anterior extension of axial mesoderm. Analysis of cultured mesoderm explants and mouse embryonic fibroblasts from null mutants shows that the mesoderm migration defect is correlated with decreased cell spreading, abnormal focal adhesions, changes in the organization of the actin cytoskeleton, and decreased velocity of cell migration. The results show that STRIPAK complexes are essential for cell migration and tissue morphogenesis in vivo.
Collapse
|
26
|
Jain BP, Pandey S, Saleem N, Tanti GK, Mishra S, Goswami SK. SG2NA is a regulator of endoplasmic reticulum (ER) homeostasis as its depletion leads to ER stress. Cell Stress Chaperones 2017; 22:853-866. [PMID: 28634818 PMCID: PMC5655373 DOI: 10.1007/s12192-017-0816-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Revised: 05/19/2017] [Accepted: 05/26/2017] [Indexed: 01/24/2023] Open
Abstract
SG2NA belongs to a three-member striatin subfamily of WD40 repeat superfamily of proteins. It has multiple protein-protein interaction domains involved in assembling supramolecular signaling complexes. Earlier, we had demonstrated that there are at least five variants of SG2NA generated by alternative splicing, intron retention, and RNA editing. Such versatile and dynamic mode of regulation implicates it in tissue development. In order to shed light on its role in cell physiology, total proteome analysis was performed in NIH3T3 cells depleted of 78 kDa SG2NA, the only isoform expressing therein. A number of ER stress markers were among those modulated after knockdown of SG2NA. In cells treated with the ER stressors thapsigargin and tunicamycin, expression of SG2NA was increased at both mRNA and protein levels. The increased level of SG2NA was primarily in the mitochondria and the microsomes. A mouse injected with thapsigargin also had an increase in SG2NA in the liver but not in the brain. Cell cycle analysis suggested that while loss of SG2NA reduces the level of cyclin D1 and retains a population of cells in the G1 phase, concurrent ER stress facilitates their exit from G1 and traverse through subsequent phases with concomitant cell death. Thus, SG2NA is a component of intrinsic regulatory pathways that maintains ER homeostasis.
Collapse
Affiliation(s)
- Buddhi Prakash Jain
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
- Department of Zoology, School of Life Sciences, Mahatma Gandhi Central University Bihar, Motihari, 845401, India
| | - Shweta Pandey
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
| | - Nikhat Saleem
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
| | - Goutam K Tanti
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India
- Neuro-Kopf-Zentrum, Department of Neurology, Klinikumrechts der Isar, School of Medicine, Technical University of Munich, Ismaninger Str.22, 81675, Muenchen, Germany
| | - Shalini Mishra
- Peptide and Proteomics Division, Defence Institute of Physiology and Allied Sciences (DIPAS), DRDO, New Delhi, -110054, India
| | - Shyamal K Goswami
- School of Life Sciences, Jawaharlal Nehru University, New Mehrauli Road, New Delhi, 110067, India.
| |
Collapse
|
27
|
Glucocorticoid Receptor-mediated transactivation is hampered by Striatin-3, a novel interaction partner of the receptor. Sci Rep 2017; 7:8941. [PMID: 28827617 PMCID: PMC5567040 DOI: 10.1038/s41598-017-09246-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 07/19/2017] [Indexed: 12/12/2022] Open
Abstract
The transcriptional activity of the glucocorticoid receptor (GR) is co-determined by its ability to recruit a vast and varying number of cofactors. We here identify Striatin-3 (STRN3) as a novel interaction partner of GR that interferes with GR’s ligand-dependent transactivation capacity. Remarkably, STRN3 selectively affects only GR-dependent transactivation and leaves GR-dependent transrepression mechanisms unhampered. We found that STRN3 down-regulates GR transactivation by an additional recruitment of the catalytic subunit of protein phosphatase 2A (PPP2CA) to GR. We hypothesize the existence of a functional trimeric complex in the nucleus, able to dephosphorylate GR at serine 211, a known marker for GR transactivation in a target gene-dependent manner. The presence of STRN3 appears an absolute prerequisite for PPP2CA to engage in a complex with GR. Herein, the C-terminal domain of GR is essential, reflecting ligand-dependency, yet other receptor parts are also needed to create additional contacts with STRN3.
Collapse
|
28
|
Nader M, Alotaibi S, Alsolme E, Khalil B, Abu-Zaid A, Alsomali R, Bakheet D, Dzimiri N. Cardiac striatin interacts with caveolin-3 and calmodulin in a calcium sensitive manner and regulates cardiomyocyte spontaneous contraction rate. Can J Physiol Pharmacol 2017; 95:1306-1312. [PMID: 28825318 DOI: 10.1139/cjpp-2017-0155] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Impaired cardiomyocyte contraction rate is detrimental to cardiac function and often lethal. Despite advancements in the field, there is a paucity of information regarding the coordination of molecules implicated in regulating the heart rate. Striatin (STRN) is a dynamic protein with binding domains to calmodulin (CaM) and caveolin (Cav), both of which are regulators of myocardial function. However, its role in cardiomyocyte contraction is not yet determined. Herein, we show that STRN is expressed in cardiomyocytes and is more abundant in atrial myocardium than in ventricles. Cardiac expression of STRN (protein and mRNA) was developmentally regulated with the highest expression being at neonatal stage (day one) and the lowest in adult rats (13 weeks). CaM pulldown assay indicated that the interaction of cardiac STRN with CaM and caveolin-3 (Cav-3) was calcium sensitive. Interestingly, the overexpression of STRN induced an increase (∼2-fold) in the rate of the spontaneous contraction of cultured cardiomyocytes, while the knockdown of STRN reduced their contraction rate (∼40%). The expression level of STRN was inversely proportional to the interaction of Cav-3 with the CaM/STRN complex. Collectively, our data delineate a novel role for STRN in regulating cardiomyocyte spontaneous contraction rate and the dynamics of the STRN/Cav-3/CaM complex.
Collapse
Affiliation(s)
- Moni Nader
- a Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh 11533, Kingdom of Saudi Arabia.,b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Shahd Alotaibi
- a Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh 11533, Kingdom of Saudi Arabia.,b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Ebtehal Alsolme
- a Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh 11533, Kingdom of Saudi Arabia.,b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Bariaa Khalil
- a Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh 11533, Kingdom of Saudi Arabia.,b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Ahmed Abu-Zaid
- a Department of Physiological Sciences, College of Medicine, Alfaisal University, Riyadh 11533, Kingdom of Saudi Arabia.,b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Rahmah Alsomali
- b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Dana Bakheet
- b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| | - Nduna Dzimiri
- b Department of Genetics, King Faisal Specialist Hospital and Research Centre, Riyadh, Kingdom of Saudi Arabia
| |
Collapse
|
29
|
Pandey S, Talukdar I, Jain BP, Tanti GK, Goswami SK. GSK3β and ERK regulate the expression of 78 kDa SG2NA and ectopic modulation of its level affects phases of cell cycle. Sci Rep 2017; 7:7555. [PMID: 28790387 PMCID: PMC5548716 DOI: 10.1038/s41598-017-08085-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 07/06/2017] [Indexed: 12/13/2022] Open
Abstract
Striatin and SG2NA are essential constituents of the multi-protein STRIPAK assembly harbouring protein phosphatase PP2A and several kinases. SG2NA has several isoforms generated by mRNA splicing and editing. While the expression of striatin is largely restricted to the striatum in brain, that of SG2NAs is ubiquitous. In NIH3T3 cells, only the 78 kDa isoform is expressed. When cells enter into the S phase, the level of SG2NA increases; reaches maximum at the G2/M phase and declines thereafter. Downregulation of SG2NA extends G1 phase and its overexpression extends G2. Ectopic expression of the 35 kDa has no effects on the cell cycle. Relative abundance of phospho-SG2NA is high in the microsome and cytosol and the nucleus but low in the mitochondria. Okadoic acid, an inhibitor of PP2A, increases the level of SG2NA which is further enhanced upon inhibition of proteasomal activity. Phospho-SG2NA is thus more stable than the dephosphorylated form. Inhibition of GSK3β by LiCl reduces its level, but the inhibition of ERK by PD98059 increases it. Thus, ERK decreases the level of phospho-SG2NA by inhibiting GSK3β. In cells depleted from SG2NA by shRNA, the levels of pGSK3β and pERK are reduced, suggesting that these kinases and SG2NA regulate each other's expression.
Collapse
Affiliation(s)
- Shweta Pandey
- School of Life Sciences, Jawaharlal Nehru University, 110067, New Delhi, India
| | - Indrani Talukdar
- School of Life Sciences, Jawaharlal Nehru University, 110067, New Delhi, India
| | - Buddhi P Jain
- School of Life Sciences, Jawaharlal Nehru University, 110067, New Delhi, India.,Department of Zoology, School of Life Sciences, Mahatma Gandhi Central University, Motihari, 845401, Bihar, India
| | - Goutam K Tanti
- School of Life Sciences, Jawaharlal Nehru University, 110067, New Delhi, India.,Department of Neurology, School of Medicine, Technical University of Munich, Munich, Germany
| | - Shyamal K Goswami
- School of Life Sciences, Jawaharlal Nehru University, 110067, New Delhi, India.
| |
Collapse
|
30
|
Islam KT, Bond JP, Fakhoury AM. FvSTR1, a striatin orthologue in Fusarium virguliforme, is required for asexual development and virulence. Appl Microbiol Biotechnol 2017; 101:6431-6445. [PMID: 28643182 DOI: 10.1007/s00253-017-8387-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 06/07/2017] [Accepted: 06/10/2017] [Indexed: 02/07/2023]
Abstract
The soil-borne fungus Fusarium virguliforme causes sudden death syndrome (SDS), one of the most devastating diseases of soybean in North and South America. Despite the importance of SDS, a clear understanding of the fungal pathogenicity factors that affect the development of this disease is still lacking. We have identified FvSTR1, a F. virguliforme gene, which encodes a protein similar to a family of striatin proteins previously reported to regulate signalling pathways, cell differentiation, conidiation, sexual development, and virulence in filamentous fungi. Striatins are multi-domain proteins that serve as scaffolding units in the striatin-interacting phosphatase and kinase (STRIPAK) complex in fungi and animals. To address the function of a striatin homologue in F. virguliforme, FvSTR1 was disrupted and functionally characterized using a gene knock out strategy. The resulting Fvstr1 mutants were largely impaired in conidiation and pigmentation, and displayed defective conidia and conidiophore morphology compared to the wild-type and ectopic transformants. Greenhouse virulence assays revealed that the disruption of FvSTR1 resulted in complete loss of virulence in F. virguliforme. Microtome studies using fluorescence microscopy showed that the Fvstr1 mutants were defective in their ability to colonize the vascular system. The Fvstr1 mutants also showed a reduced transcript level of genes involved in asexual reproduction and in the production of secondary metabolites. These results suggest that FvSTR1 has a critical role in asexual development and virulence in F. virguliforme.
Collapse
Affiliation(s)
- Kazi T Islam
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA
- Donald Danforth Plant Science Center, St Louis, MO, 63132, USA
| | - Jason P Bond
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA
| | - Ahmad M Fakhoury
- Department of Plant, Soil and Agriculture Systems, Southern Illinois University, Carbondale, IL, 62901, USA.
| |
Collapse
|
31
|
Keeley TP, Siow RCM, Jacob R, Mann GE. A PP2A-mediated feedback mechanism controls Ca 2+-dependent NO synthesis under physiological oxygen. FASEB J 2017; 31:5172-5183. [PMID: 28760745 PMCID: PMC5690389 DOI: 10.1096/fj.201700211r] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Accepted: 07/17/2017] [Indexed: 12/20/2022]
Abstract
Intracellular O2 is a key regulator of NO signaling, yet most in vitro studies are conducted in atmospheric O2 levels, hyperoxic with respect to the physiologic milieu. We investigated NO signaling in endothelial cells cultured in physiologic (5%) O2 and stimulated with histamine or shear stress. Culture of cells in 5% O2 (>5 d) decreased histamine- but not shear stress–stimulated endothelial (e)NOS activity. Unlike cells adapted to a hypoxic environment (1% O2), those cultured in 5% O2 still mobilized sufficient Ca2+ to activate AMPK. Enhanced expression and membrane targeting of PP2A-C was observed in 5% O2, resulting in greater interaction with eNOS in response to histamine. Moreover, increased dephosphorylation of eNOS in 5% O2 was Ca2+-sensitive and reversed by okadaic acid or PP2A-C siRNA. The present findings establish that Ca2+ mobilization stimulates both NO synthesis and PP2A-mediated eNOS dephosphorylation, thus constituting a novel negative feedback mechanism regulating eNOS activity not present in response to shear stress. This, coupled with enhanced NO bioavailability, underpins differences in NO signaling induced by inflammatory and physiologic stimuli that are apparent only in physiologic O2 levels. Furthermore, an explicit delineation between physiologic normoxia and genuine hypoxia is defined here, with implications for our understanding of pathophysiological hypoxia.—Keeley, T. P., Siow, R. C. M., Jacob, R., Mann, G. E. A PP2A-mediated feedback mechanism controls Ca2+-dependent NO synthesis under physiological oxygen.
Collapse
Affiliation(s)
- Thomas P Keeley
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Richard C M Siow
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Ron Jacob
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| | - Giovanni E Mann
- Cardiovascular Division, King's British Heart Foundation Centre of Research Excellence, Faculty of Life Sciences and Medicine, King's College London, London, United Kingdom
| |
Collapse
|
32
|
Wang X, Mu Y, Sun M, Han J. Bidirectional regulation of fragile X mental retardation protein phosphorylation controls rhodopsin homoeostasis. J Mol Cell Biol 2017; 9:104-116. [PMID: 27702760 DOI: 10.1093/jmcb/mjw041] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Accepted: 09/29/2016] [Indexed: 01/03/2023] Open
Abstract
Homoeostatic regulation of the light sensor, rhodopsin, is critical for the maintenance of light sensitivity and survival of photoreceptors. The major fly rhodopsin, Rh1, undergoes light-induced endocytosis and degradation, but its protein and mRNA levels remain constant during light/dark cycles. It is not clear how translation of Rh1 is regulated. Here, we show that adult photoreceptors maintain a constant, abundant quantity of ninaE mRNA, which encodes Rh1. We demonstrate that the Fmr1 protein associates with ninaE mRNA and represses its translation. Further, light exposure triggers a calcium-dependent dephosphorylation of Fmr1, which relieves suppression of Rh1 translation. We demonstrate that Mts, the catalytic subunit of protein phosphatase 2A (PP2A), mediates light-induced Fmr1 dephosphorylation in a regulatory B subunit of PP2A (CKa)-dependent manner. Finally, we show that blocking light-induced Rh1 translation results in reduced light sensitivity. Our results reveal the molecular mechanism of Rh1 homoeostasis and physiological consequence of Rh1 dysregulation.
Collapse
Affiliation(s)
- Xiao Wang
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Yawen Mu
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Mengshi Sun
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China
| | - Junhai Han
- Institute of Life Sciences, The Key Laboratory of Developmental Genes and Human Disease, Southeast University, Nanjing 210096, China.,Co-innovation Center of Neuroregeneration, Nantong University, Nantong 226001, China
| |
Collapse
|
33
|
Lin L, Lo LHY, Lyu Q, Lai KO. Determination of dendritic spine morphology by the striatin scaffold protein STRN4 through interaction with the phosphatase PP2A. J Biol Chem 2017; 292:9451-9464. [PMID: 28442576 DOI: 10.1074/jbc.m116.772442] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 04/15/2017] [Indexed: 11/06/2022] Open
Abstract
Dendritic spines are heterogeneous and exist with various morphologies. Altered spine morphology might underlie the cognitive deficits in neurodevelopmental disorders such as autism, but how different subtypes of dendritic spines are selectively maintained along development is still poorly understood. Spine maturation requires spontaneous activity of N-methyl-d-aspartate (NMDA) receptor and local dendritic protein synthesis. STRN4 (also called zinedin) belongs to the striatin family of scaffold proteins, and some of the potential striatin-interacting proteins are encoded by autism risk genes. Although previous studies have demonstrated their localization in dendritic spines, the function of various striatin family members in the neuron remains unknown. Here, we demonstrate that Strn4 mRNA is present in neuronal dendrites, and the local expression of STRN4 protein depends on NMDA receptor activation. Notably, STRN4 is preferentially expressed in mushroom spines, and STRN4 specifically maintains mushroom spines but not thin spines and filopodia through interaction with the phosphatase PP2A. Our findings have therefore unraveled the local expression of STRN4 as a novel mechanism for the control of dendritic spine morphology.
Collapse
Affiliation(s)
| | | | | | - Kwok-On Lai
- From the School of Biomedical Sciences and .,State Key Laboratory of Brain and Cognitive Sciences, University of Hong Kong, Hong Kong, China
| |
Collapse
|
34
|
Lai TY, Yen CJ, Tsai HW, Yang YS, Hong WF, Chiang CW. The B56γ3 regulatory subunit-containing protein phosphatase 2A outcompetes Akt to regulate p27KIP1 subcellular localization by selectively dephosphorylating phospho-Thr157 of p27KIP1. Oncotarget 2016; 7:4542-58. [PMID: 26684356 PMCID: PMC4826225 DOI: 10.18632/oncotarget.6609] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 12/02/2015] [Indexed: 01/01/2023] Open
Abstract
The B56γ-containing protein phosphatase 2A (PP2A-B56γ) has been postulated to have tumor suppressive functions. Here, we report regulation of p27KIP1 subcellular localization by PP2A-B56γ3. B56γ3 overexpression enhanced nuclear localization of p27KIP1, whereas knockdown of B56γ3 decreased p27KIP1 nuclear localization. B56γ3 overexpression decreased phosphorylation at Thr157 (phospho-Thr157), whose phosphorylation promotes cytoplasmic localization of p27KIP1, whereas B56γ3 knockdown significantly increased the level of phospho-Thr157. In vitro, PP2A-B56γ3 catalyzed dephosphorylation of phospho-Thr157 in a dose-dependent and okadaic acid-sensitive manner. B56γ3 did not increase p27KIP1 nuclear localization by down-regulating the upstream kinase Akt activity and outcompeted a myristoylated constitutively active Akt (Aktca) in regulating Thr157 phosphorylation and subcellular localization of p27KIP1. In addition, results of interaction domain mapping revealed that both the N-terminal and C-terminal domains of p27 and a domain at the C-terminus of B56γ3 are required for interaction between p27 and B56γ3. Furthermore, we demonstrated that p27KIP1 levels are positively correlated with B56γ levels in both non-tumor and tumor parts of a set of human colon tissue specimens. However, positive correlation between nuclear p27KIP1 levels and B56γ levels was found only in the non-tumor parts, but not in tumor parts of these tissues, implicating a dysregulation in PP2A-B56γ3-regulated p27KIP1 nuclear localization in these tumor tissues. Altogether, this study provides a new mechanism by which the PP2A-B56γ3 holoenzyme plays its tumor suppressor role.
Collapse
Affiliation(s)
- Tai-Yu Lai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chia-Jui Yen
- Department of Internal Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Clinical Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Wen Tsai
- Department of Pathology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-San Yang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Wei-Fu Hong
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chi-Wu Chiang
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan.,Center for Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| |
Collapse
|
35
|
Juraszek B, Nałęcz KA. Protein phosphatase PP2A - a novel interacting partner of carnitine transporter OCTN2 (SLC22A5) in rat astrocytes. J Neurochem 2016; 139:537-551. [DOI: 10.1111/jnc.13777] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2016] [Revised: 07/15/2016] [Accepted: 08/08/2016] [Indexed: 11/29/2022]
Affiliation(s)
- Barbara Juraszek
- Laboratory of Transport through Biomembranes; Department of Molecular and Cellular Neurobiology; Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| | - Katarzyna A. Nałęcz
- Laboratory of Transport through Biomembranes; Department of Molecular and Cellular Neurobiology; Nencki Institute of Experimental Biology of Polish Academy of Sciences; Warsaw Poland
| |
Collapse
|
36
|
The broken "Off" switch in cancer signaling: PP2A as a regulator of tumorigenesis, drug resistance, and immune surveillance. BBA CLINICAL 2016; 6:87-99. [PMID: 27556014 PMCID: PMC4986044 DOI: 10.1016/j.bbacli.2016.08.002] [Citation(s) in RCA: 112] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/01/2016] [Accepted: 08/02/2016] [Indexed: 12/31/2022]
Abstract
Aberrant activation of signal transduction pathways can transform a normal cell to a malignant one and can impart survival properties that render cancer cells resistant to therapy. A diverse set of cascades have been implicated in various cancers including those mediated by serine/threonine kinases such RAS, PI3K/AKT, and PKC. Signal transduction is a dynamic process involving both "On" and "Off" switches. Activating mutations of RAS or PI3K can be viewed as the switch being stuck in the "On" position resulting in continued signaling by a survival and/or proliferation pathway. On the other hand, inactivation of protein phosphatases such as the PP2A family can be seen as the defective "Off" switch that similarly can activate these pathways. A problem for therapeutic targeting of PP2A is that the enzyme is a hetero-trimer and thus drug targeting involves complex structures. More importantly, since PP2A isoforms generally act as tumor suppressors one would want to activate these enzymes rather than suppress them. The elucidation of the role of cellular inhibitors like SET and CIP2A in cancer suggests that targeting these proteins can have therapeutic efficacy by mechanisms involving PP2A activation. Furthermore, drugs such as FTY-720 can activate PP2A isoforms directly. This review will cover the current state of knowledge of PP2A role as a tumor suppressor in cancer cells and as a mediator of processes that can impact drug resistance and immune surveillance.
Collapse
|
37
|
Wang CL, Shim WB, Shaw BD. The Colletotrichum graminicola striatin orthologue Str1 is necessary for anastomosis and is a virulence factor. MOLECULAR PLANT PATHOLOGY 2016; 17:931-42. [PMID: 26576029 PMCID: PMC6638439 DOI: 10.1111/mpp.12339] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/19/2015] [Accepted: 10/20/2015] [Indexed: 05/24/2023]
Abstract
Striatin family proteins are key regulators in signalling pathways in fungi and animals. These scaffold proteins contain four conserved domains: a caveolin-binding domain, a coiled-coil motif and a calmodulin-binding domain at the N-terminus, and a WD-repeat domain at the C-terminus. Fungal striatin orthologues are associated with sexual development, hyphal growth and plant pathogenesis. In Fusarium verticillioides, the striatin orthologue Fsr1 promotes virulence in the maize stalk. The relationship between fungal striatins and pathogenicity remains largely unexplored. In this study, we demonstrate that the Colletotrichum graminicola striatin orthologue Str1 is required for full stalk rot and leaf blight virulence in maize. Pathogenicity assays show that the striatin mutant strain (Δstr1) produces functional appressoria, but infection and colonization are attenuated. Additional phenotypes of the Δstr1 mutant include reduced radial growth and compromised hyphal fusion. In comparison with the wild-type, Δstr1 also shows a defect in sexual development and produces fewer and shorter conidia. Together with the fact that F. verticillioides fsr1 can complement Δstr1, our results indicate that C. graminicola Str1 shares five phenotypes with striatin orthologues in other fungal species: hyphal growth, hyphal fusion, conidiation, sexual development and virulence. We propose that fungal striatins, like mammalian striatins, act as scaffolding molecules that cross-link multiple signal transduction pathways.
Collapse
Affiliation(s)
- Chih-Li Wang
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, TX, USA
- Department of Plant Pathology, National Chung Hsing University, Taichung 40227, Taiwan
| | - Won-Bo Shim
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, TX, USA
| | - Brian D Shaw
- Department of Plant Pathology and Microbiology, Texas A&M University, College Station 77843-2132, TX, USA
| |
Collapse
|
38
|
Abstract
Protein phosphatase 2A (PP2A) plays a critical multi-faceted role in the regulation of the cell cycle. It is known to dephosphorylate over 300 substrates involved in the cell cycle, regulating almost all major pathways and cell cycle checkpoints. PP2A is involved in such diverse processes by the formation of structurally distinct families of holoenzymes, which are regulated spatially and temporally by specific regulators. Here, we review the involvement of PP2A in the regulation of three cell signaling pathways: wnt, mTOR and MAP kinase, as well as the G1→S transition, DNA synthesis and mitotic initiation. These processes are all crucial for proper cell survival and proliferation and are often deregulated in cancer and other diseases.
Collapse
Affiliation(s)
- Nathan Wlodarchak
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
| | - Yongna Xing
- a McArdle Laboratory for Cancer Research, University of Wisconsin-Madison , Madison , WI , USA
| |
Collapse
|
39
|
Shi Z, Jiao S, Zhou Z. STRIPAK complexes in cell signaling and cancer. Oncogene 2016; 35:4549-57. [PMID: 26876214 DOI: 10.1038/onc.2016.9] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/24/2015] [Accepted: 12/24/2015] [Indexed: 12/28/2022]
Abstract
Striatin-interacting phosphatase and kinase (STRIPAK) complexes are striatin-centered multicomponent supramolecular structures containing both kinases and phosphatases. STRIPAK complexes are evolutionarily conserved and have critical roles in protein (de)phosphorylation. Recent studies indicate that STRIPAK complexes are emerging mediators and regulators of multiple vital signaling pathways including Hippo, MAPK (mitogen-activated protein kinase), nuclear receptor and cytoskeleton remodeling. Different types of STRIPAK complexes are extensively involved in a variety of fundamental biological processes ranging from cell growth, differentiation, proliferation and apoptosis to metabolism, immune regulation and tumorigenesis. Growing evidence correlates dysregulation of STRIPAK complexes with human diseases including cancer. In this review, we summarize the current understanding of the assembly and functions of STRIPAK complexes, with a special focus on cell signaling and cancer.
Collapse
Affiliation(s)
- Z Shi
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - S Jiao
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Z Zhou
- State Key Laboratory of Cell Biology, CAS Center for Excellence in Molecular Cell Science, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China.,School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| |
Collapse
|
40
|
Dudiki T, Kadunganattil S, Ferrara JK, Kline DW, Vijayaraghavan S. Changes in Carboxy Methylation and Tyrosine Phosphorylation of Protein Phosphatase PP2A Are Associated with Epididymal Sperm Maturation and Motility. PLoS One 2015; 10:e0141961. [PMID: 26569399 PMCID: PMC4646675 DOI: 10.1371/journal.pone.0141961] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 10/15/2015] [Indexed: 01/21/2023] Open
Abstract
Mammalian sperm contain the serine/threonine phosphatases PP1γ2 and PP2A. The role of sperm PP1γ2 is relatively well studied. Here we confirm the presence of PP2A in sperm and show that it undergoes marked changes in methylation (leucine 309), tyrosine phosphorylation (tyrosine 307) and catalytic activity during epididymal sperm maturation. Spermatozoa isolated from proximal caput, distal caput and caudal regions of the epididymis contain equal immuno-reactive amounts of PP2A. Using demethyl sensitive antibodies we show that PP2A is methylated at its carboxy terminus in sperm from the distal caput and caudal regions but not in sperm from the proximal caput region of the epididymis. The methylation status of PP2A was confirmed by isolation of PP2A with microcystin agarose followed by alkali treatment, which causes hydrolysis of protein carboxy methyl esters. Tyrosine phosphorylation of sperm PP2A varied inversely with methylation. That is, PP2A was tyrosine phosphorylated when it was demethylated but not when methylated. PP2A demethylation and its reciprocal tyrosine phosphorylation were also affected by treatment of sperm with L-homocysteine and adenosine, which are known to elevate intracellular S-adenosylhomocysteine, a feedback inhibitor of methyltransferases. Catalytic activity of PP2A declined during epididymal sperm maturation. Inhibition of PP2A by okadaic acid or by incubation of caudal epididymal spermatozoa with L-homocysteine and adenosine resulted in increase of sperm motility parameters including percent motility, velocity, and lateral head amplitude. Demethylation or pharmacological inhibition of PP2A also leads to an increase in phosphorylation of glycogen synthase kinase-3 (GSK3). Our results show for the first time that changes in PP2A activity due to methylation and tyrosine phosphorylation occur in sperm and that these changes may play an important role in the regulation of sperm function.
Collapse
Affiliation(s)
- Tejasvi Dudiki
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - Suraj Kadunganattil
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - John K. Ferrara
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | - Douglas W. Kline
- Department of Biological Sciences, Kent State University, Kent, Ohio, United States of America
| | | |
Collapse
|
41
|
Kück U, Beier AM, Teichert I. The composition and function of the striatin-interacting phosphatases and kinases (STRIPAK) complex in fungi. Fungal Genet Biol 2015; 90:31-38. [PMID: 26439752 DOI: 10.1016/j.fgb.2015.10.001] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Revised: 09/30/2015] [Accepted: 10/02/2015] [Indexed: 02/06/2023]
Abstract
The striatin-interacting phosphatases and kinases (STRIPAK) complex is a highly conserved eukaryotic protein complex that was recently described for diverse animal and fungal species. Here, we summarize our current knowledge about the composition and function of the STRIPAK complex from the ascomycete Sordaria macrospora, which we discovered by investigating sexually sterile mutants (pro), having a defect in fruiting body development. Mass spectrometry and yeast two-hybrid analysis defined core subunits of the STRIPAK complex, which have structural homologs in animal and other fungal organisms. These subunits (and their mammalian homologs) are PRO11 (striatin), PRO22 (STRIP1/2), SmMOB3 (Mob3), PRO45 (SLMAP), and PP2AA, the structural, and PP2Ac, the catalytic subunits of protein phosphatase 2A (PP2A). Beside fruiting body formation, the STRIPAK complex controls vegetative growth and hyphal fusion in S. macrospora. Although the contribution of single subunits to diverse cellular and developmental processes is not yet fully understood, functional analysis has already shown that mammalian homologs are able to substitute the function of distinct fungal STRIPAK subunits. This underscores the view that fungal model organisms serve as useful tools to get a molecular insight into cellular and developmental processes of eukaryotes in general. Future work will unravel the precise localization of single subunits within the cell and decipher their STRIPAK-related and STRIPAK-independent functions. Finally, evidence is accumulating that there is a crosstalk between STRIPAK and various signaling pathways, suggesting that eukaryotic development is dependent on STRIPAK signaling.
Collapse
Affiliation(s)
- Ulrich Kück
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany.
| | - Anna M Beier
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany
| | - Ines Teichert
- Lehrstuhl für Allgemeine und Molekulare Botanik, Ruhr-University Bochum, Universitätsstr. 150, 44780 Bochum, Germany
| |
Collapse
|
42
|
Guffroy A, Dima A, Nespola B, Poindron V, Sibilia J, Herbrecht R, De Sèze J, Habersetzer F, Andres E, Quoix E, Ohlmann P, Cribier B, Langer B, Martin T, Pasquali JL, Goetz J, Korganow AS. Anti-pseudo-PCNA type 1 (anti-SG2NA) pattern: Track down Cancer, not SLE. Joint Bone Spine 2015; 83:330-4. [PMID: 26433710 DOI: 10.1016/j.jbspin.2015.07.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2015] [Accepted: 07/22/2015] [Indexed: 11/18/2022]
Abstract
OBJECTIVE Describe the clinical significance of anti-SG2NA antibodies also called anti-pseudo-PCNA type 1 (proliferating cell nuclear antigen auto-antibodies) which are rare antinuclear antibodies (ANAs) staining distinctly S/G2 proliferative HEp-2 cells by indirect immunofluorescence. By analogy with anti-PCNA antibodies, they have been suspected to be associated with systemic lupus erythematosus (SLE), cancers or viral diseases. METHODS From May 2006 to February 2013, 16,827 patients were tested positive for ANAs in the Laboratory of Immunology, Strasbourg, France. We retrospectively analyzed clinical and biological data from 126 patients with anti-pseudo-PCNA type 1 antibodies. RESULTS There was a 0.75% prevalence of anti-pseudo-PCNA type 1 Abs among ANAs(+) patients. Median age was 56.9 years (standard deviation [SD] 13.4 years) with a sex ratio female/male of 1.9. Compared to ANAs(+) patients, many more patients have been hospitalized in the Oncology and Hematology Department (23% vs. 6.3%, P < 0.05). Indeed, anti-pseudo-PCNA type 1 Abs were detected in 33 patients suffering from solid and hematological cancers (26%). Another group of patients presented various auto-immune diseases but surprisingly none of our patients was affected with SLE when 5 out of 8 patients in anti-PCNAs(+) Abs group (P < 5.10(-6)) were. Finally, the presence of anti-pseudo-PCNA type 1 Abs was associated in 30 cases with other auto-Abs reflecting a more general breakdown of B cell tolerance against other self-antigens. CONCLUSION Considering our results, explorations for tumors should be at least recommended for patients with anti-pseudo-PCNA type 1 Abs. Lupus disease is not associated with these autoAbs.
Collapse
Affiliation(s)
- Aurélien Guffroy
- Department of Clinical Immunology and Internal Medicine, National Reference Center for Autoimmune Diseases, Strasbourg Hospital and University, 1, place de l'Hôpital, 67091 Strasbourg, France; Department of Rheumatology, National Reference Center for Autoimmune Diseases, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Alina Dima
- Department of Internal Medicine, Colentina Clinical Hospital, 72202 Bucharest, Romania
| | - Benoit Nespola
- Laboratory of Immunology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Vincent Poindron
- Department of Clinical Immunology and Internal Medicine, National Reference Center for Autoimmune Diseases, Strasbourg Hospital and University, 1, place de l'Hôpital, 67091 Strasbourg, France
| | - Jean Sibilia
- Department of Rheumatology, National Reference Center for Autoimmune Diseases, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Raoul Herbrecht
- Department of Oncology and Hematology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Jerome De Sèze
- Department of Neurology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - François Habersetzer
- Department of Gastro-Enterology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Emmanuel Andres
- Department of Internal Medicine B, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Elisabeth Quoix
- Department of Pneumology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Patrick Ohlmann
- Department of Cardiology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Bernard Cribier
- Department of Dermatology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Bruno Langer
- Maternity Ward, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Thierry Martin
- Department of Clinical Immunology and Internal Medicine, National Reference Center for Autoimmune Diseases, Strasbourg Hospital and University, 1, place de l'Hôpital, 67091 Strasbourg, France
| | - Jean-Louis Pasquali
- Department of Clinical Immunology and Internal Medicine, National Reference Center for Autoimmune Diseases, Strasbourg Hospital and University, 1, place de l'Hôpital, 67091 Strasbourg, France
| | - Joëlle Goetz
- Laboratory of Immunology, Strasbourg Hospital and University, 67000 Strasbourg, France
| | - Anne-Sophie Korganow
- Department of Clinical Immunology and Internal Medicine, National Reference Center for Autoimmune Diseases, Strasbourg Hospital and University, 1, place de l'Hôpital, 67091 Strasbourg, France.
| |
Collapse
|
43
|
Kurimchak A, Graña X. PP2A: more than a reset switch to activate pRB proteins during the cell cycle and in response to signaling cues. Cell Cycle 2015; 14:18-30. [PMID: 25483052 PMCID: PMC4612414 DOI: 10.4161/15384101.2014.985069] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
In their active hypophosphorylated state, members of the retinoblastoma family of pocket proteins negatively regulate cell cycle progression at least in part by repressing expression of E2F-dependent genes. Mitogen-dependent activation of G1 and G1/S Cyclin Dependent Kinases (CDKs) results in coordinated hyperphosphorylation and inactivation of these proteins, which no longer bind and repress E2Fs. S and G2/M CDKs maintain pocket protein hyperphosphorylated through the end of mitosis. The inactivating action of inducible CDKs is opposed by the Ser/Thr protein phosphatases PP2A and PP1. Various trimeric PP2A holoenzymes have been implicated in dephosphorylation of pocket proteins in response to specific cellular signals and stresses or as part of an equilibrium with CDKs throughout the cell cycle. PP1 has specifically been implicated in dephosphorylation of pRB in late mitosis and early G1. This review is particularly focused on the emerging role of PP2A as a major hub for integration of growth suppressor signals that require rapid inactivation of pocket proteins. Of note, activation of particular PP2A holoenzymes triggers differential activation of pocket proteins in the presence of active CDKs.
Collapse
Affiliation(s)
- Alison Kurimchak
- a Fels Institute for Cancer Research and Molecular Biology and Department of Biochemistry; Temple University School of Medicine ; Philadelphia , PA USA
| | | |
Collapse
|
44
|
Zheng S, Chen X, Hong S, Long L, Xu Y, Simoncini T, Fu X. 17β-Estradiol inhibits vascular smooth muscle cell migration via up-regulation of striatin protein. Gynecol Endocrinol 2015. [PMID: 26220767 DOI: 10.3109/09513590.2015.1021325] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Striatin, an estrogen receptor (ER)-interacting protein, plays an important role in estrogen's nongenomic actions in vascular endothelial cells. However, the role of striatin in VSMCs is unknown. Here, we investigated the role of striatin in estrogen-regulated VSMCs migration. 17β-Estradiol (E2) at 10 nM largely inhibited VSMCs migration, which was reversed by the silencing of striatin expression. E2 increased striatin protein expression in a dose- and time-dependent manner. ERα agonist PPT, but not ERβ agonist DPN, mimicked the regulatory effect of E2. The regulatory effect of E2 on striatin protein expression was blocked by the pure ER antagonist ICI 182,780 or the mitogen-activated protein kinase inhibitor PD98059, but not by the phosphatidylinositol-3 kinase inhibitor wortmannin or Src inhibitor PP2, suggesting that E2 increased striatin protein expression via extracellular-signal regulated kinase 1/2 (ERK1/2). E2 resulted in phosphorylation of ERK1/2 in a time-dependent manner. The silencing of ERK1/2 largely abolished E2-enhanced striatin expression. Finally, the inhibitory effect of E2 on VSMC migration was reversed by ICI 182,780 or PD98059. Taken together, our results indicate that E2 inhibits VSMC migration by increasing striatin expression via ERα to ERK1/2 pathway, which maybe helpful to understand estrogen's anti-atherogenic effect in VSMCs.
Collapse
Affiliation(s)
- Shuhui Zheng
- a Research Center of Translational Medicine, the First Affiliated Hospital, Sun Yat-Sen University , Guangzhou , Guangdong Province , China
| | - Xi Chen
- b Department of Rehabilitation Medicine , the Third Affiliated Hospital, Sun Yat-sen University , Guangzhou , Guangdong Province , China
| | - Shubin Hong
- c Department of Endocrinology , the First Affiliated Hospital, Sun Yat-Sen University , Guangzhou , Guangdong Province , China
| | - Lingli Long
- a Research Center of Translational Medicine, the First Affiliated Hospital, Sun Yat-Sen University , Guangzhou , Guangdong Province , China
| | - Yuxia Xu
- a Research Center of Translational Medicine, the First Affiliated Hospital, Sun Yat-Sen University , Guangzhou , Guangdong Province , China
| | - Tommaso Simoncini
- d Molecular and Cellular Gynecological Endocrinology Laboratory (MCGEL), Department of Reproductive Medicine and Child Development , University of Pisa , Pisa , Italy , and
| | - Xiaodong Fu
- e School of Basic Sciences, Guangzhou Medical University , Guangzhou , Guangdong Province , China
| |
Collapse
|
45
|
Mo ST, Chiang SJ, Lai TY, Cheng YL, Chung CE, Kuo SCH, Reece KM, Chen YC, Chang NS, Wadzinski BE, Chiang CW. Visualization of subunit interactions and ternary complexes of protein phosphatase 2A in mammalian cells. PLoS One 2014; 9:e116074. [PMID: 25536081 PMCID: PMC4275284 DOI: 10.1371/journal.pone.0116074] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Accepted: 12/01/2014] [Indexed: 11/18/2022] Open
Abstract
Protein phosphatase 2A (PP2A) is a ubiquitous phospho-serine/threonine phosphatase that controls many diverse cellular functions. The predominant form of PP2A is a heterotrimeric holoenzyme consisting of a scaffolding A subunit, a variable regulatory B subunit, and a catalytic C subunit. The C subunit also associates with other interacting partners, such as α4, to form non-canonical PP2A complexes. We report visualization of PP2A complexes in mammalian cells. Bimolecular fluorescence complementation (BiFC) analysis of PP2A subunit interactions demonstrates that the B subunit plays a key role in directing the subcellular localization of PP2A, and confirms that the A subunit functions as a scaffold in recruiting the B and C subunits to form a heterotrimeric holoenzyme. BiFC analysis also reveals that α4 promotes formation of the AC core dimer. Furthermore, we demonstrate visualization of specific ABC holoenzymes in cells by combining BiFC and fluorescence resonance energy transfer (BiFC-FRET). Our studies not only provide direct imaging data to support previous biochemical observations on PP2A complexes, but also offer a promising approach for studying the spatiotemporal distribution of individual PP2A complexes in cells.
Collapse
Affiliation(s)
- Shu-Ting Mo
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shang-Ju Chiang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Tai-Yu Lai
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Yu-Ling Cheng
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Cheng-En Chung
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Spencer C. H. Kuo
- Department of Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Kelie M. Reece
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States of America
| | - Yung-Cheng Chen
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Nan-Shan Chang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center for Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
| | - Brian E. Wadzinski
- Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN, United States of America
- * E-mail: (CWC); (BEW)
| | - Chi-Wu Chiang
- Institute of Molecular Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Center for Infectious Disease and Signaling Research, National Cheng Kung University, Tainan, Taiwan
- * E-mail: (CWC); (BEW)
| |
Collapse
|
46
|
Franke WW, Rickelt S, Zimbelmann R, Dörflinger Y, Kuhn C, Frey N, Heid H, Rosin-Arbesfeld R. Striatins as plaque molecules of zonulae adhaerentes in simple epithelia, of tessellate junctions in stratified epithelia, of cardiac composite junctions and of various size classes of lateral adherens junctions in cultures of epithelia- and carcinoma-derived cells. Cell Tissue Res 2014; 359:779-97. [PMID: 25501894 PMCID: PMC4341017 DOI: 10.1007/s00441-014-2053-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Accepted: 11/05/2014] [Indexed: 11/29/2022]
Abstract
Proteins of the striatin family (striatins 1–4; sizes ranging from 90 to 110 kDa on SDS-polyacrylamide gel electrophoresis) are highly homologous in their amino acid sequences but can differ in their cell-type-specific gene expression patterns and biological functions. In various cell types, we have found one, two or three polypeptides of this evolutionarily old and nearly ubiquitous family of proteins known to serve as scaffold proteins for diverse protein complexes. Light and electron microscopic immunolocalization methods have revealed striatins in mammalian cell-cell adherens junctions (AJs). In simple epithelia, we have localized striatins as constitutive components of the plaques of the subapical zonulae adhaerentes of cells, including intestinal, glandular, ductal and urothelial cells and hepatocytes. Striatins colocalize with E-cadherin or E–N-cadherin heterodimers and with the plaque proteins α- and β-catenin, p120 and p0071. In some epithelia and carcinomas and in cultured cells derived therefrom, striatins are also seen in lateral AJs. In stratified epithelia and in corresponding squamous cell carcinomas, striatins can be found in plaques of some forms of tessellate junctions. Moreover, striatins are major plaque proteins of composite junctions (CJs; areae compositae) in the intercalated disks connecting cardiomyocytes, colocalizing with other CJ molecules, including plectin and ankyrin-G. We discuss the “multimodulator” scaffold roles of striatins in the initiation and regulation of the formation of various complex particles and structures. We propose that striatins are included in the diagnostic candidate list of proteins that, in the CJs of human hearts, can occur in mutated forms in the pathogeneses of hereditary cardiomyopathies, as seen in some types of genetically determined heart damage in boxer dogs.
Collapse
Affiliation(s)
- Werner W Franke
- Helmholtz Group for Cell Biology, German Cancer Research Center (DKFZ), Im Neuenheimer Feld 280, 69120, Heidelberg, Germany,
| | | | | | | | | | | | | | | |
Collapse
|
47
|
Kaźmierczak-Barańska J, Pęczek Ł, Przygodzka P, Cieślak MJ. Downregulation of striatin leads to hyperphosphorylation of MAP2, induces depolymerization of microtubules and inhibits proliferation of HEK293T cells. FEBS Lett 2014; 589:222-30. [PMID: 25497017 DOI: 10.1016/j.febslet.2014.12.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Revised: 11/25/2014] [Accepted: 12/02/2014] [Indexed: 01/11/2023]
Abstract
Microtubules are tubular polymers of α/β-tubulin that are involved in the maintenance of cell shape, motility, and intracellular transport and in the segregation of chromosomes during cell division. Microtubules are dynamic structures, and their assembly is regulated by phosphoproteins called microtubule-associated proteins (MAPs). We propose that striatin, a protein belonging to the striatin family of proteins, is involved in regulation of microtubules. In HEK293T cells, striatin colocalizes with microtubules and stably associates with PP2Ac. Inhibition of striatin expression results in hyperphosphorylation of MAP2 and destabilizes microtubules. Striatin-induced destabilization of microtubules inhibited the proliferation of HEK293T cells and caused the accumulation of cells in the G0/G1 phase of the cell cycle. These results suggest that the PP2A/striatin complex modulates microtubule dynamics by regulating MAP2 phosphorylation.
Collapse
Affiliation(s)
- Julia Kaźmierczak-Barańska
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 112 Sienkiewicza St., 90-363 Lodz, Poland.
| | - Łukasz Pęczek
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 112 Sienkiewicza St., 90-363 Lodz, Poland
| | - Patrycja Przygodzka
- Institute for Medical Biology of the Polish Academy of Sciences, 106 Lodowa St., 93-232 Lodz, Poland.
| | - Marcin J Cieślak
- Department of Bioorganic Chemistry, Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 112 Sienkiewicza St., 90-363 Lodz, Poland.
| |
Collapse
|
48
|
Tissue specific expression of SG2NA is regulated by differential splicing, RNA editing and differential polyadenylation. Gene 2014; 556:119-26. [PMID: 25459749 DOI: 10.1016/j.gene.2014.11.045] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Revised: 11/05/2014] [Accepted: 11/20/2014] [Indexed: 11/21/2022]
Abstract
SG2NA belongs to a three member Striatin subfamily of WD-40 repeat superfamily. It has multiple protein-protein interaction domains that are involved in the assembly of supra-molecular signaling complexes. Earlier we had demonstrated that there are at least five variants of SG2NA, generated by alternative splicing. We now demonstrate that a 52kDa novel variant is generated by the editing of the transcript for the 82kDa isoform. The 52kDa protein is abundant in mouse tissues but it is barely present in immortalized cells, suggesting its role in cell differentiation. Besides splicing and editing, expression of SG2NAs in tissues is also regulated by differential polyadenylation and mRNA/protein stability. Further, the longer UTR is seen only in the brain mRNA from 1month old mouse and 8-10day old chick embryo. Like alternative splicing, differential polyadenylation of Sg2na transcripts is also conserved in evolution. Taken together, these results suggest a highly versatile and dynamic mode of regulation of SG2NA with potential implications in tissue development.
Collapse
|
49
|
Wong M, Hyodo T, Asano E, Funasaka K, Miyahara R, Hirooka Y, Goto H, Hamaguchi M, Senga T. Silencing of STRN4 suppresses the malignant characteristics of cancer cells. Cancer Sci 2014; 105:1526-32. [PMID: 25250919 PMCID: PMC4317966 DOI: 10.1111/cas.12541] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2014] [Revised: 08/17/2014] [Accepted: 09/18/2014] [Indexed: 12/23/2022] Open
Abstract
The striatin family of proteins, comprising STRN, STRN3 and STRN4, are multidomain-containing proteins that associate with additional proteins to form a large protein complex. We previously reported that STRN4 directly associated with protein kinases, such as MINK1, TNIK and MAP4K4, which are associated with tumor suppression or tumor progression. However, it remains unclear whether STRN4 is associated with tumor progression. In this report, we examined the role that STRN4 plays in cancer malignancy. We show that depletion of STRN4 suppresses proliferation, migration, invasion and the anchorage-independent growth of cancer cells. In addition, STRN4 knockdown increases the sensitivity of pancreatic cancer cells to gemcitabine. Finally, we show that STRN4 knockdown suppresses the proliferation and metastasis of cancer cells in mice. Our results demonstrate a possible role of STRN4 in tumor progression.
Collapse
Affiliation(s)
- Meihong Wong
- Department of Gastroenterology and Hepatology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | | | | | | | | | | | | | | | | |
Collapse
|
50
|
Chen C, Shi Z, Zhang W, Chen M, He F, Zhang Z, Wang Y, Feng M, Wang W, Zhao Y, Brown JH, Jiao S, Zhou Z. Striatins contain a noncanonical coiled coil that binds protein phosphatase 2A A subunit to form a 2:2 heterotetrameric core of striatin-interacting phosphatase and kinase (STRIPAK) complex. J Biol Chem 2014; 289:9651-61. [PMID: 24550388 PMCID: PMC3975014 DOI: 10.1074/jbc.m113.529297] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2013] [Revised: 02/17/2014] [Indexed: 01/18/2023] Open
Abstract
The protein phosphatase 2A (PP2A) and kinases such as germinal center kinase III (GCKIII) can interact with striatins to form a supramolecular complex called striatin-interacting phosphatase and kinase (STRIPAK) complex. Despite the fact that the STRIPAK complex regulates multiple cellular events, it remains only partially understood how this complex itself is assembled and regulated for differential biological functions. Our recent work revealed the activation mechanism of GCKIIIs by MO25, as well as how GCKIIIs heterodimerize with CCM3, a molecular bridge between GCKIII and striatins. Here we dissect the structural features of the coiled coil domain of striatin 3, a novel type of PP2A regulatory subunit that functions as a scaffold for the assembly of the STRIPAK complex. We have determined the crystal structure of a selenomethionine-labeled striatin 3 coiled coil domain, which shows it to assume a parallel dimeric but asymmetric conformation containing a large bend. This result combined with a number of biophysical analyses provide evidence that the coiled coil domain of striatin 3 and the PP2A A subunit form a stable core complex with a 2:2 stoichiometry. Structure-based mutational studies reveal that homodimerization of striatin 3 is essential for its interaction with PP2A and therefore assembly of the STRIPAK complex. Wild-type striatin 3 but not the mutants defective in PP2A binding strongly suppresses apoptosis of Jurkat cells induced by the GCKIII kinase MST3, most likely through a mechanism in which striatin recruits PP2A to negatively regulate the activation of MST3. Collectively, our work provides structural insights into the organization of the STRIPAK complex and will facilitate further functional studies.
Collapse
Affiliation(s)
- Cuicui Chen
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhubing Shi
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- the School of Life Sciences and Technology, Tongji University, Shanghai 200092, China, and
| | - Wenqing Zhang
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Min Chen
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Feng He
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhenzhen Zhang
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yicui Wang
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Miao Feng
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Wenjia Wang
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Yun Zhao
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Jerry H. Brown
- the Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, Massachusetts 02454-9110
| | - Shi Jiao
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Zhaocai Zhou
- From the National Center for Protein Science Shanghai, State Key Laboratory of Cell Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
- the School of Life Sciences and Technology, Tongji University, Shanghai 200092, China, and
| |
Collapse
|