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Atajanova T, Kang EM, Postnikova A, Price AL, Doerr S, Du M, Ugenti A, Ragkousi K. Lateral cell polarization drives organization of epithelia in sea anemone embryos and embryonic cell aggregates. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.07.588493. [PMID: 38645007 PMCID: PMC11030385 DOI: 10.1101/2024.04.07.588493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
One of the first organizing processes during animal development is the assembly of embryonic cells into epithelia. In certain animals, including Hydra and sea anemones, epithelia also emerge when cells from dissociated tissues are aggregated back together. Although cell adhesion is required to keep cells together, it is not clear whether cell polarization plays a role as epithelia emerge from disordered aggregates. Here, we demonstrate that lateral cell polarization is essential for epithelial organization in both embryos and aggregates of the sea anemone Nematostella vectensis. Specifically, knock down of the lateral polarity protein Lgl disrupts epithelia in developing embryos and impairs the capacity of dissociated cells to epithelialize from aggregates. Cells in lgl mutant epithelia lose their columnar shape and have mispositioned mitotic spindles and ciliary basal bodies. Together, our data suggest that in Nematostella, Lgl is required to establish lateral cell polarity and position cytoskeletal organelles in cells of embryos and aggregates during de novo epithelial organization.
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Affiliation(s)
- Tavus Atajanova
- Department of Biology, Amherst College, Amherst, MA 01002, USA
- Present address: Dana-Farber Cancer Institute, Boston, MA 02215, USA
| | | | - Anna Postnikova
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | | | - Sophia Doerr
- Department of Biology, Amherst College, Amherst, MA 01002, USA
- Present address: Department of Biology, Institute of Molecular Biology, University of Oregon, Eugene, OR 97403, USA
| | - Michael Du
- Department of Biology, Amherst College, Amherst, MA 01002, USA
| | - Alicia Ugenti
- Department of Biology, Amherst College, Amherst, MA 01002, USA
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2
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Deng M, Liu B, Zhang Z, Chen Y, Wang Y, Wang X, Lv Q, Yang X, Hou K, Che X, Qu X, Liu Y, Zhang Y, Hu X. Loss of G-protein-signaling modulator 2 accelerates proliferation of lung adenocarcinoma via EGFR signaling pathway. Int J Biochem Cell Biol 2020; 122:105716. [PMID: 32058048 DOI: 10.1016/j.biocel.2020.105716] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/31/2020] [Accepted: 02/10/2020] [Indexed: 12/20/2022]
Abstract
G-protein-signaling modulator 2 (GPSM2) belongs to a protein family that regulates activation of G proteins and plays an important role in mitotic spindle orientation. However, the role of GPSM2 in lung adenocarcinoma (LUAD) is still unclear. In this study, it was found that GPSM2 correlates with clinicopathological features and patient's prognosis in LUAD. Knocking down GPSM2 promoted LUAD cell proliferation in vitro and in vivo. Mechanistically, it was demonstrated that GPSM2 knockdown accelerates cell proliferation via the EGFR pathway. These results confirmed that GPSM2 played an important role in LUAD. Moreover, GPSM2, as an independent prognostic factor, may serve as a potential drug target and prognostic biomarker in LUAD.
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Affiliation(s)
- Mingming Deng
- Department of Respiratory and Infectious Disease of Geriatrics, The First Hospital of China Medical University, Shenyang 110001, China; Department of Pulmonary and Critical Care Medicine, Center of Respiratory Medicine, China-Japan Friendship Hospital, Beijing, China; Graduate School of Peking Union Medical College, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Bofang Liu
- Department of Medical Oncology, Sir Run Run Shaw Hospital, College of Medicine, Zhejiang University, Hangzhou 310000, Zhejiang, China
| | - Zhe Zhang
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang 110001, China
| | - Yang Chen
- Department of Respiratory and Infectious Disease of Geriatrics, The First Hospital of China Medical University, Shenyang 110001, China
| | - Yizhe Wang
- Department of Respiratory and Infectious Disease of Geriatrics, The First Hospital of China Medical University, Shenyang 110001, China
| | - Ximing Wang
- Department of Respiratory and Infectious Disease of Geriatrics, The First Hospital of China Medical University, Shenyang 110001, China
| | - Qingjie Lv
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang 110001, China
| | - Xianghong Yang
- Department of Pathology, Shengjing Hospital of China Medical University, Shenyang 110001, China
| | - Kezuo Hou
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang 110001, China
| | - Xiaofang Che
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang 110001, China
| | - Xiujuan Qu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang 110001, China
| | - Yunpeng Liu
- Department of Medical Oncology, The First Hospital of China Medical University, Shenyang 110001, China
| | - Ye Zhang
- The First Laboratory of Cancer Institute, The First Hospital of China Medical University, Shenyang 110001, China.
| | - Xuejun Hu
- Department of Respiratory and Infectious Disease of Geriatrics, The First Hospital of China Medical University, Shenyang 110001, China.
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Takayanagi H, Hayase J, Kamakura S, Miyano K, Chishiki K, Yuzawa S, Sumimoto H. Intramolecular interaction in LGN, an adaptor protein that regulates mitotic spindle orientation. J Biol Chem 2019; 294:19655-19666. [PMID: 31732560 DOI: 10.1074/jbc.ra119.011457] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 11/07/2019] [Indexed: 12/11/2022] Open
Abstract
Proper mitotic spindle orientation requires that astral microtubules are connected to the cell cortex by the microtubule-binding protein NuMA, which is recruited from the cytoplasm. Cortical recruitment of NuMA is at least partially mediated via direct binding to the adaptor protein LGN. LGN normally adopts a closed conformation via an intramolecular interaction between its N-terminal NuMA-binding domain and its C-terminal region that contains four GoLoco (GL) motifs, each capable of binding to the membrane-anchored Gαi subunit of heterotrimeric G protein. Here we show that the intramolecular association with the N-terminal domain in LGN involves GL3, GL4, and a region between GL2 and GL3, whereas GL1 and GL2 do not play a major role. This conformation renders GL1 but not the other GL motifs in a state easily accessible to Gαi To interact with full-length LGN in a closed state, NuMA requires the presence of Gαi; both NuMA and Gαi are essential for cortical recruitment of LGN in mitotic cells. In contrast, mInsc, a protein that competes with NuMA for binding to LGN and regulates mitotic spindle orientation in asymmetric cell division, efficiently binds to full-length LGN without Gαi and induces its conformational change, enhancing its association with Gαi In nonpolarized symmetrically dividing HeLa cells, disruption of the LGN-NuMA interaction by ectopic expression of mInsc results in a loss of cortical localization of NuMA during metaphase and anaphase and promotes mitotic spindle misorientation and a delayed anaphase progression. These findings highlight a specific role for LGN-mediated cell cortex recruitment of NuMA.
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Affiliation(s)
- Hiroki Takayanagi
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Junya Hayase
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Sachiko Kamakura
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Kei Miyano
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Kanako Chishiki
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Satoru Yuzawa
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
| | - Hideki Sumimoto
- Department of Biochemistry, Kyushu University Graduate School of Medical Sciences, Fukuoka 812-8582, Japan
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4
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Structural insights into the aPKC regulatory switch mechanism of the human cell polarity protein lethal giant larvae 2. Proc Natl Acad Sci U S A 2019; 116:10804-10812. [PMID: 31088962 DOI: 10.1073/pnas.1821514116] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Metazoan cell polarity is controlled by a set of highly conserved proteins. Lethal giant larvae (Lgl) functions in apical-basal polarity through phosphorylation-dependent interactions with several other proteins as well as the plasma membrane. Phosphorylation of Lgl by atypical protein kinase C (aPKC), a component of the partitioning-defective (Par) complex in epithelial cells, excludes Lgl from the apical membrane, a crucial step in the establishment of epithelial cell polarity. We present the crystal structures of human Lgl2 in both its unphosphorylated and aPKC-phosphorylated states. Lgl2 adopts a double β-propeller structure that is unchanged by aPKC phosphorylation of an unstructured loop in its second β-propeller, ruling out models of phosphorylation-dependent conformational change. We demonstrate that phosphorylation controls the direct binding of purified Lgl2 to negative phospholipids in vitro. We also show that a coil-helix transition of this region that is promoted by phosphatidylinositol 4,5-bisphosphate (PIP2) is also phosphorylation-dependent, implying a highly effective phosphorylative switch for membrane association.
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5
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Kujawski S, Sonawane M, Knust E. penner/lgl2 is required for the integrity of the photoreceptor layer in the zebrafish retina. Biol Open 2019; 8:8/4/bio041830. [PMID: 31015218 PMCID: PMC6503998 DOI: 10.1242/bio.041830] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The vertebrate retina is a complex tissue built from multiple neuronal cell types, which develop from a pseudostratified neuroepithelium. These cells are arranged into a highly organized and stereotypic pattern formed by nuclear and plexiform layers. The process of lamination as well as the maturation and differentiation of photoreceptor cells rely on the establishment and maintenance of apico-basal cell polarity and formation of adhesive junctions. Defects in any of these processes can result in impaired vision and are causally related to a variety of human diseases leading to blindness. While the importance of apical polarity regulators in retinal stratification and disease is well established, little is known about the function of basal regulators in retinal development. Here, we analyzed the role of Lgl2, a basolateral polarity factor, in the zebrafish retina. Lgl2 is upregulated in photoreceptor cells and in the retinal pigment epithelium by 72 h post fertilization. In both cell types, Lgl2 is localized basolaterally. Loss of zygotic Lgl2 does not interfere with retinal lamination or photoreceptor cell polarity or maturation. However, knockdown of both maternal and zygotic Lgl2 leads to impaired cell adhesion. As a consequence, severe layering defects occur in the distal retina, manifested by a breakdown of the outer plexiform layer and the outer limiting membrane. These results define zebrafish Lgl2 as an important regulator of retinal lamination, which, given the high degree of evolutionary conservation, may be preserved in other vertebrates, including human. Summary: Knockdown of penner/lgl2 leads to a breakdown of the outer plexiform layer and the outer limiting membrane in the zebrafish retina due to impaired cell adhesion.
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Affiliation(s)
- Satu Kujawski
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108 01307 Dresden, Germany
| | - Mahendra Sonawane
- Tata Institute of Fundamental Research, Department of Biological Sciences, Homi Bhabha Road, Navy Nagar, Colaba, Mumbai 400005, India
| | - Elisabeth Knust
- Max-Planck-Institute of Molecular Cell Biology and Genetics, Pfotenhauerstrasse 108 01307 Dresden, Germany
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Moreira S, Morais-de-Sá E. Spatiotemporal phosphoregulation of Lgl: Finding meaning in multiple on/off buttons. BIOARCHITECTURE 2016; 6:29-38. [PMID: 26919260 DOI: 10.1080/19490992.2016.1149290] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Intracellular asymmetries, often termed cell polarity, determine how cells organize and divide to ultimately control cell fate and shape animal tissues. The tumor suppressor Lethal giant larvae (Lgl) functions at the core of the evolutionarily conserved cell polarity machinery that controls apico-basal polarization. This function relies on its restricted basolateral localization via phosphorylation by aPKC. Here, we summarize the spatial and temporal control of Lgl during the cell cycle, highlighting two ideas that emerged from our recent findings: 1) Aurora A directly phosphorylates Lgl during symmetric division to couple reorganization of epithelial polarity with the cell cycle; 2) Phosphorylation of Lgl within three conserved serines controls its localization and function in a site-specific manner. Considering the importance of phosphorylation to regulate the concentration of Lgl at the plasma membrane, we will further discuss how it may work as an on-off switch for the interaction with cortical binding partners, with implications on epithelial polarization and spindle orientation.
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Affiliation(s)
- Sofia Moreira
- a IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto , Porto , Portugal.,b I3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto , Porto , Portugal
| | - Eurico Morais-de-Sá
- a IBMC, Instituto de Biologia Molecular e Celular, Universidade do Porto , Porto , Portugal.,b I3S, Instituto de Investigação e Inovação em Saúde, Universidade do Porto , Porto , Portugal
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7
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Poly-L-lysine Prevents Senescence and Augments Growth in Culturing Mesenchymal Stem Cells Ex Vivo. BIOMED RESEARCH INTERNATIONAL 2016; 2016:8196078. [PMID: 27403437 PMCID: PMC4925960 DOI: 10.1155/2016/8196078] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/23/2016] [Indexed: 12/17/2022]
Abstract
Mesenchymal stem cells (MSCs) possess great therapeutic potential. Efficient in vitro expansion of MSCs is however necessary for their clinical application. The extracellular matrix (ECM) provides structural and biochemical support to the surrounding cells, and it has been used as a coating substrate for cell culture. In this study, we have aimed to improve the functionality and stemness of MSCs during culture using poly-L-lysine (PLL). Functionality of MSCs was analysed by cell cycle analysis, differentiation assay, β-galactosidase staining, and RT-PCR. Furthermore, we assessed the global gene expression profile of MSCs on uncoated and PLL-coated plates. MSCs on PLL-coated plates exhibited a faster growth rate with increased S-phase and upregulated expression of the stemness markers. In addition, their osteogenic differentiation potential was increased, and genes involved in cell adhesion, FGF-2 signalling, cell cycle, stemness, cell differentiation, and cell proliferation were upregulated, compared to that of the MSCs cultured on uncoated plates. We also confirmed that MSCs on uncoated plates expressed higher β-galactosidase than the MSCs on PLL-coated plates. We demonstrate that PLL provides favourable microenvironment for MSC culture by reversing the replicative senescence. This method will significantly contribute to effective preparation of MSCs for cellular therapy.
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8
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Abba ML, Patil N, Leupold JH, Allgayer H. MicroRNA Regulation of Epithelial to Mesenchymal Transition. J Clin Med 2016; 5:jcm5010008. [PMID: 26784241 PMCID: PMC4730133 DOI: 10.3390/jcm5010008] [Citation(s) in RCA: 81] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 12/18/2015] [Accepted: 01/05/2016] [Indexed: 02/07/2023] Open
Abstract
Epithelial to mesenchymal transition (EMT) is a central regulatory program that is similar in many aspects to several steps of embryonic morphogenesis. In addition to its physiological role in tissue repair and wound healing, EMT contributes to chemo resistance, metastatic dissemination and fibrosis, amongst others. Classically, the morphological change from epithelial to mesenchymal phenotype is characterized by the appearance or loss of a group of proteins which have come to be recognized as markers of the EMT process. As with all proteins, these molecules are controlled at the transcriptional and translational level by transcription factors and microRNAs, respectively. A group of developmental transcription factors form the backbone of the EMT cascade and a large body of evidence shows that microRNAs are heavily involved in the successful coordination of mesenchymal transformation and vice versa, either by suppressing the expression of different groups of transcription factors, or otherwise acting as their functional mediators in orchestrating EMT. This article dissects the contribution of microRNAs to EMT and analyzes the molecular basis for their roles in this cellular process. Here, we emphasize their interaction with core transcription factors like the zinc finger enhancer (E)-box binding homeobox (ZEB), Snail and Twist families as well as some pluripotency transcription factors.
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Affiliation(s)
- Mohammed L Abba
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
| | - Nitin Patil
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
| | - Jörg Hendrik Leupold
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
| | - Heike Allgayer
- Department of Experimental Surgery, Center for Biomedicine and Medical Technology Mannheim (CBTM), Medical Faculty Mannheim, Ruprecht Karl University of Heidelberg, Ludolf-Krehl-Str. 6, 68135 Mannheim, Germany.
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9
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Yamada Y, Matsui K, Takeuchi I, Oguri M, Fujimaki T. Association of genetic variants with hypertension in a longitudinal population-based genetic epidemiological study. Int J Mol Med 2015; 35:1189-98. [PMID: 25813534 PMCID: PMC4380208 DOI: 10.3892/ijmm.2015.2151] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Accepted: 03/03/2015] [Indexed: 01/11/2023] Open
Abstract
We previously identified 9 genes and chromosomal region 3q28 as susceptibility loci for Japanese patients with myocardial infarction, ischemic stroke, or chronic kidney disease by genome-wide or candidate gene association studies. In the present study, we investigated the possible association of 13 single nucleotide polymorphisms (SNPs) at these 10 loci with the prevalence of hypertension or their association with blood pressure (BP) in community-dwelling individuals in Japan. The study subjects comprised 6,027 individuals (2,250 subjects with essential hypertension, 3,777 controls) who were recruited into the Inabe Health and Longevity Study, a longitudinal genetic epidemiological study on atherosclerotic, cardiovascular and metabolic diseases. The subjects were recruited from individuals who visited the Health Care Center of Inabe General Hospital for an annual health checkup, and they are followed up each year (mean follow-up period, 5 years). Longitudinal analysis with a generalized estimating equation and with adjustment for age, gender, body mass index and smoking status revealed that rs2116519 of family with sequence similarity 78, member B (FAM78B; P=0.0266), rs6929846 of butyrophilin, subfamily 2, member A1 (BTN2A1; P= 0.0013), rs146021107 of pancreatic and duodenal homeobox 1 (PDX1; P=0.0031) and rs1671021 of lethal giant larvae homolog 2 (Drosophila) (LLGL2; P=0.0372) were significantly (P<0.05) associated with the prevalence of hypertension. Longitudinal analysis with a generalized linear mixed-effect model and with adjustment for age, gender, body mass index and smoking status among individuals not taking anti-hypertensive medication revealed that rs6929846 of BTN2A1 was significantly associated with systolic (P=0.0017), diastolic (P=0.0008) and mean (P=0.0005) BP, and that rs2116519 of FAM78B, rs146021107 of PDX1 and rs1671021 of LLGL2 were significantly associated with diastolic (P=0.0495), systolic (P=0.0132), and both diastolic (P=0.0468) and mean (0.0471) BP, respectively. BTN2A1 may thus be a susceptibility gene for hypertension.
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Affiliation(s)
- Yoshiji Yamada
- Department of Human Functional Genomics, Life Science Research Center, Mie University, Tsu, Mie 514‑8507, Japan
| | - Kota Matsui
- Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency, Tokyo 102‑0076, Japan
| | - Ichiro Takeuchi
- Core Research for Evolutionary Science and Technology (CREST), Japan Science and Technology Agency, Tokyo 102‑0076, Japan
| | - Mitsutoshi Oguri
- Department of Cardiology, Japanese Red Cross Nagoya First Hospital, Nagoya 453-8511, Japan
| | - Tetsuo Fujimaki
- Department of Cardiovascular Medicine, Inabe General Hospital, Inabe, Mie 511-0428, Japan
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10
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Cao F, Miao Y, Xu K, Liu P. Lethal (2) giant larvae: an indispensable regulator of cell polarity and cancer development. Int J Biol Sci 2015; 11:380-9. [PMID: 25798058 PMCID: PMC4366637 DOI: 10.7150/ijbs.11243] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 01/21/2015] [Indexed: 01/04/2023] Open
Abstract
Cell polarity is one of the most basic properties of all normal cells and is essential for regulating numerous biological processes. Loss of polarity is considered a hallmark for cancer. Multiple polarity proteins are implicated in maintenance of cell polarity. Lethal (2) giant larvae (Lgl) is one of polarity proteins that plays an important role in regulating cell polarity, asymmetric division as well as tumorigenesis. Lgl proteins in different species have similar structures and conserved functions. Lgl acts as an indispensable regulator of cell biological function, including cell polarity and asymmetric division, through interplaying with other polarity proteins, regulating exocytosis, mediating cytoskeleton and being involved in signaling pathways. Furthermore, Lgl plays a role of a tumor suppressor, and the aberrant expression of Hugl, a human homologue of Lgl, contributes to multiple cancers. However, the exact functions of Lgl and the underlying mechanisms remain enigmatic. In this review, we will give an overview of the Lgl functions in cell polarity and cancer development, discuss the potential mechanisms underlying these functions, and raise our conclusion of previous studies and points of view about the future studies.
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Affiliation(s)
- Fang Cao
- 1. Center for Translational Medicine, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
| | - Yi Miao
- 1. Center for Translational Medicine, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
| | - Kedong Xu
- 2. Department of Hepatobiliary Surgery, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
| | - Peijun Liu
- 1. Center for Translational Medicine, The First Affiliated Hospital of Xian Jiaotong University, College of Medicine, Xi'an, China
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11
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Carvalho CA, Moreira S, Ventura G, Sunkel CE, Morais-de-Sá E. Aurora A triggers Lgl cortical release during symmetric division to control planar spindle orientation. Curr Biol 2014; 25:53-60. [PMID: 25484294 DOI: 10.1016/j.cub.2014.10.053] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/23/2014] [Accepted: 10/21/2014] [Indexed: 11/30/2022]
Abstract
Mitotic spindle orientation is essential to control cell-fate specification and epithelial architecture. The tumor suppressor Lgl localizes to the basolateral cortex of epithelial cells, where it acts together with Dlg and Scrib to organize apicobasal polarity. Dlg and Scrib also control planar spindle orientation, but how the organization of polarity complexes is adjusted to control symmetric division is largely unknown. Here, we show that the Dlg complex is remodeled during Drosophila follicular epithelium cell division, when Lgl is released to the cytoplasm. Lgl redistribution during epithelial mitosis is reminiscent of asymmetric cell division, where it is proposed that Aurora A promotes aPKC activation to control the localization of Lgl and cell-fate determinants. We show that Aurora A controls Lgl localization directly, triggering its cortical release at early prophase in both epithelial and S2 cells. This relies on double phosphorylation within the putative aPKC phosphorylation site, which is required and sufficient for Lgl cortical release during mitosis and can be achieved by a combination of aPKC and Aurora A activities. Cortical retention of Lgl disrupts planar spindle orientation, but only when Lgl mutants that can bind Dlg are expressed. Hence, our work reveals that Lgl mitotic cortical release is not specifically linked to the asymmetric segregation of fate determinants, and we propose that Aurora A activation breaks the Dlg/Lgl interaction to allow planar spindle orientation during symmetric division via the Pins (LGN)/Dlg pathway.
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Affiliation(s)
- Cátia A Carvalho
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
| | - Sofia Moreira
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
| | - Guilherme Ventura
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal
| | - Cláudio E Sunkel
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal; Instituto de Ciências Biomédicas de Abel Salazar (ICBAS), Universidade do Porto, Rua de Jorge Viterbo Ferreira 228, 4050-313 Porto, Portugal
| | - Eurico Morais-de-Sá
- Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Rua do Campo Alegre 823, 4150-180 Porto, Portugal.
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12
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Aviner R, Geiger T, Elroy-Stein O. Novel proteomic approach (PUNCH-P) reveals cell cycle-specific fluctuations in mRNA translation. Genes Dev 2013; 27:1834-44. [PMID: 23934657 PMCID: PMC3759699 DOI: 10.1101/gad.219105.113] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Monitoring protein synthesis is required to understand gene expression regulation. Aviner et al. developed a system-wide proteomic approach for direct monitoring of translation, termed puromycin-associated nascent chain proteomics (PUNCH-P), which is based on incorporation of biotinylated puromycin into newly synthesized proteins followed by streptavidin affinity purification and LC-MS/MS analysis. Using PUNCH-P, cell cycle-specific fluctuations in synthesis for >5000 proteins were measured in mammalian cells. This approach also identified proteins not previously implicated in cell cycle processes and proteins that were not detected using other methods. Monitoring protein synthesis is essential to our understanding of gene expression regulation, as protein abundance is thought to be predominantly controlled at the level of translation. Mass-spectrometric and RNA sequencing methods have been recently developed for investigating mRNA translation at a global level, but these still involve technical limitations and are not widely applicable. In this study, we describe a novel system-wide proteomic approach for direct monitoring of translation, termed puromycin-associated nascent chain proteomics (PUNCH-P), which is based on incorporation of biotinylated puromycin into newly synthesized proteins under cell-free conditions followed by streptavidin affinity purification and liquid chromatography-tandem mass spectrometry analysis. Using PUNCH-P, we measured cell cycle-specific fluctuations in synthesis for >5000 proteins in mammalian cells, identified proteins not previously implicated in cell cycle processes, and generated the first translational profile of a whole mouse brain. This simple and economical technique is broadly applicable to any cell type and tissue, enabling the identification and quantification of rapid proteome responses under various biological conditions.
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Affiliation(s)
- Ranen Aviner
- Department of Cell Research and Immunology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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13
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Mapelli M, Gonzalez C. On the inscrutable role of Inscuteable: structural basis and functional implications for the competitive binding of NuMA and Inscuteable to LGN. Open Biol 2013; 2:120102. [PMID: 22977735 PMCID: PMC3438535 DOI: 10.1098/rsob.120102] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2012] [Accepted: 07/20/2012] [Indexed: 11/12/2022] Open
Abstract
Alignment of the mitotic spindle to the cellular polarity axis is a prerequisite for asymmetric cell divisions. The protein network coordinating the spindle position with cortical polarity includes the molecular machinery pulling on astral microtubules, which is assembled on conserved NuMA:LGN:Gαi complexes, the polarity proteins Par3:Par6:aPKC and an adaptor molecule known as Inscuteable (Insc). To date, all these components were assumed to enter a macromolecular complex localized at polarity sites in mitosis. However, recent structural studies revealed the Insc and NuMA are mutually exclusive interactors of LGN, implying that the molecular mechanism of spindle coupling to polarity is more sophisticated than has been believed to date.
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Affiliation(s)
- Marina Mapelli
- Department of Experimental Oncology, European Institute of Oncology, Via Adamello 16, 20139 Milan, Italy.
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14
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Structural and biochemical characterization of the interaction between LGN and Frmpd1. J Mol Biol 2013; 425:1039-49. [PMID: 23318951 DOI: 10.1016/j.jmb.2013.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 12/28/2012] [Accepted: 01/07/2013] [Indexed: 11/21/2022]
Abstract
The tetratricopeptide repeat (TPR) motif-containing protein LGN binds multiple targets and regulates their subcellular localizations and functions during both asymmetric and symmetric cell divisions. Here, we characterized the interaction between LGN-TPR motifs and FERM and PDZ domain containing 1 (Frmpd1) and reported the crystal structure of the complex at 2.4Å resolution. A highly conserved fragment at the center of Frmpd1 of ~20 residues was found to be necessary and sufficient to bind to LGN-TPR. This Frmpd1 fragment forms an extended structure and runs along the concave channel of the TPR superhelix in an antiparallel manner in the complex. Structural comparisons and biochemical studies of LGN/Frmpd1 and other known LGN/target interactions demonstrate that the LGN-TPR motifs are versatile and capable of recognizing multiple targets via diverse binding modes. Nevertheless, a conserved "E/QxEx4-5E/D/Qx1-2K/R" motif in LGN/Pins (partner of inscuteable) TPR binding proteins has been identified.
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15
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Diaz-Horta O, Sirmaci A, Doherty D, Nance W, Arnos K, Pandya A, Tekin M. GPSM2 mutations in Chudley-McCullough syndrome. Am J Med Genet A 2012; 158A:2972-3. [PMID: 22987632 DOI: 10.1002/ajmg.a.35636] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2012] [Accepted: 07/24/2012] [Indexed: 12/27/2022]
Affiliation(s)
- Oscar Diaz-Horta
- Dr. John T. Macdonald Foundation Department of Human Genetics, Miller School of Medicine, University of Miami, Miami, Florida 33136, USA
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16
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Peyre E, Morin X. An oblique view on the role of spindle orientation in vertebrate neurogenesis. Dev Growth Differ 2012; 54:287-305. [PMID: 22524602 DOI: 10.1111/j.1440-169x.2012.01350.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Neurogenesis is a dynamic process that produces a diverse number of glial and neural cell types from a limited number of neural stem cells throughout development and into adulthood. After an initial period of amplification through symmetric division, neural stem cells rely on asymmetric modes of division to self-renew while producing more committed progeny. Understanding the molecular mechanisms regulating the choice between symmetric and asymmetric modes of division is essential to understand human brain development and pathologies, and to explain the increasing cortical complexity observed in evolution. A popular model states the existence of a causal relationship between the orientation of the axis of division of stem cells and the fate of their progeny in many different tissues, but the validity of the model in neural stem cells is not clear. In this review, we briefly present the diversity of neural stem cells and intermediate progenitors in the developing central nervous system. We then draw a historic overview of the assumed causal relationship between spindle orientation and fate determination. We show how this prompted a search for regulators of spindle orientation, and present the current state of knowledge on the mechanism. Finally, we review data on the effect of defective spindle orientation and try to integrate conflicting observations by presenting alternative mechanisms that may regulate the choice between symmetric and asymmetric outcomes.
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Affiliation(s)
- Elise Peyre
- Institut de Biologie du Développement de Marseille-Luminy, CNRS UMR, 6216, case 907, Parc scientifique de Luminy, 13288, Marseille Cedex 9, France
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17
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Blumer JB, Oner SS, Lanier SM. Group II activators of G-protein signalling and proteins containing a G-protein regulatory motif. Acta Physiol (Oxf) 2012; 204:202-18. [PMID: 21615707 DOI: 10.1111/j.1748-1716.2011.02327.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Beyond the core triad of receptor, Gαβγ and effector, there are multiple accessory proteins that provide alternative modes of signal input and regulatory adaptability to G-protein signalling systems. Such accessory proteins may segregate a signalling complex to microdomains of the cell, regulate the basal activity, efficiency and specificity of signal propagation and/or serve as alternative binding partners for Gα or Gβγ independent of the classical heterotrimeric Gαβγ complex. The latter concept led to the postulate that Gα and Gβγ regulate intracellular events distinct from their role as transducers for cell surface seven-transmembrane span receptors. One general class of such accessory proteins is defined by AGS proteins or activators of G-protein signalling that refer to mammalian cDNAs identified in a specific yeast-based functional screen. The discovery of AGS proteins and related entities revealed a number of unexpected mechanisms for regulation of G-protein signalling systems and expanded functional roles for this important signalling system.
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Affiliation(s)
- J B Blumer
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Medical University of South Carolina, Charleston, 29425, USA
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18
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Yoshiura S, Ohta N, Matsuzaki F. Tre1 GPCR signaling orients stem cell divisions in the Drosophila central nervous system. Dev Cell 2011; 22:79-91. [PMID: 22178499 DOI: 10.1016/j.devcel.2011.10.027] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Revised: 09/14/2011] [Accepted: 10/26/2011] [Indexed: 11/20/2022]
Abstract
During development, directional cell division is a major mechanism for establishing the orientation of tissue growth. Drosophila neuroblasts undergo asymmetric divisions perpendicular to the overlying epithelium to produce descendant neurons on the opposite side, thereby orienting initial neural tissue growth. However, the mechanism remains elusive. We provide genetic evidence that extrinsic GPCR signaling determines the orientation of cortical polarity underlying asymmetric divisions of neuroblasts relative to the epithelium. The GPCR Tre1 activates the G protein oα subunit in neuroblasts by interacting with the epithelium to recruit Pins, which regulates spindle orientation. Because Pins associates with the Par-complex via Inscuteable, Tre1 consequently recruits the polarity complex to orthogonally orient the polarity axis to the epithelium. Given the universal role of the Par complex in cellular polarization, we propose that the GPCR-Pins system is a comprehensive mechanism controlling tissue polarity by orienting polarized stem cells and their divisions.
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Affiliation(s)
- Shigeki Yoshiura
- RIKEN Center for Developmental Biology, 2-2-3 Minatojima-Minamimachi, Chuo-ku, Kobe 650-0047, Japan
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19
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Yariz KO, Walsh T, Akay H, Duman D, Akkaynak AC, King MC, Tekin M. A truncating mutation in GPSM2 is associated with recessive non-syndromic hearing loss. Clin Genet 2011; 81:289-93. [PMID: 21348867 DOI: 10.1111/j.1399-0004.2011.01654.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Hereditary deafness is a genetically heterogeneous phenotype for which more than 100 genomic loci have been identified thus far. By analysis of a consanguineous Palestinian family, GPSM2 was recently discovered to be the cause of autosomal recessive non-syndromic hearing loss DFNB82. Here, we report a second truncating mutation, GPSM2 p.Q562X, identified via autozygosity mapping in a consanguineous Turkish family. This report provides evidence for allelic heterogeneity of GPSM2 and confirms its causative role for non-syndromic deafness.
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Affiliation(s)
- K O Yariz
- Dr. John T. Macdonald Foundation Department of Human Genetics and John P. Hussman Institute for Human Genomics, Miller School of Medicine, University of Miami, Miami, FL, USA
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20
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Fukukawa C, Ueda K, Nishidate T, Katagiri T, Nakamura Y. Critical roles of LGN/GPSM2 phosphorylation by PBK/TOPK in cell division of breast cancer cells. Genes Chromosomes Cancer 2010; 49:861-72. [DOI: 10.1002/gcc.20795] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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21
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Zheng Z, Zhu H, Wan Q, Liu J, Xiao Z, Siderovski DP, Du Q. LGN regulates mitotic spindle orientation during epithelial morphogenesis. ACTA ACUST UNITED AC 2010; 189:275-88. [PMID: 20385777 PMCID: PMC2856901 DOI: 10.1083/jcb.200910021] [Citation(s) in RCA: 145] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Coordinated cell polarization and mitotic spindle orientation are thought to be important for epithelial morphogenesis. Whether spindle orientation is indeed linked to epithelial morphogenesis and how it is controlled at the molecular level is still unknown. Here, we show that the NuMA- and Galpha-binding protein LGN is required for directing spindle orientation during cystogenesis of MDCK cells. LGN localizes to the lateral cell cortex, and is excluded from the apical cell cortex of dividing cells. Depleting LGN, preventing its cortical localization, or disrupting its interaction with endogenous NuMA or Galpha proteins all lead to spindle misorientation and abnormal cystogenesis. Moreover, artificial mistargeting of endogenous LGN to the apical membrane results in a near 90 degrees rotation of the spindle axis and profound cystogenesis defects that are dependent on cell division. The normal apical exclusion of LGN during mitosis appears to be mediated by atypical PKC. Thus, cell polarization-mediated spatial restriction of spindle orientation determinants is critical for epithelial morphogenesis.
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Affiliation(s)
- Zhen Zheng
- Institute of Molecular Medicine and Genetics, Medical College of Georgia, Augusta, GA 30912, USA
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22
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Yamada Y, Fuku N, Tanaka M, Aoyagi Y, Sawabe M, Metoki N, Yoshida H, Satoh K, Kato K, Watanabe S, Nozawa Y, Hasegawa A, Kojima T. Identification of CELSR1 as a susceptibility gene for ischemic stroke in Japanese individuals by a genome-wide association study. Atherosclerosis 2009; 207:144-9. [DOI: 10.1016/j.atherosclerosis.2009.03.038] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2009] [Revised: 03/26/2009] [Accepted: 03/26/2009] [Indexed: 01/06/2023]
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23
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Powell AE, Shung CY, Saylor KW, Müllendorff KA, Weiss JB, Wong MH. Lessons from development: A role for asymmetric stem cell division in cancer. Stem Cell Res 2009; 4:3-9. [PMID: 19853549 DOI: 10.1016/j.scr.2009.09.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Revised: 09/21/2009] [Accepted: 09/21/2009] [Indexed: 01/09/2023] Open
Abstract
Asymmetric stem cell division has emerged as a major regulatory mechanism for physiologic control of stem cell numbers. Reinvigoration of the cancer stem cell theory suggests that tumorigenesis may be regulated by maintaining the balance between asymmetric and symmetric cell division. Therefore, mutations affecting this balance could result in aberrant expansion of stem cells. Although a number of molecules have been implicated in regulation of asymmetric stem cell division, here, we highlight known tumor suppressors with established roles in this process. While a subset of these tumor suppressors were originally defined in developmental contexts, recent investigations reveal they are also lost or mutated in human cancers. Mutations in tumor suppressors involved in asymmetric stem cell division provide mechanisms by which cancer stem cells can hyperproliferate and offer an intriguing new focus for understanding cancer biology. Our discussion of this emerging research area derives insight from a frontier area of basic science and links these discoveries to human tumorigenesis. This highlights an important new focus for understanding the mechanism underlying expansion of cancer stem cells in driving tumorigenesis.
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Affiliation(s)
- Anne E Powell
- Department of Cell and Developmental Biology, Oregon Health & Science University, 3181 SW Sam Jackson Park Road, Portland, OR 97239, USA
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24
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Yamamoto Y, Mochida S, Kurooka T, Sakisaka T. Reciprocal intramolecular interactions of tomosyn control its inhibitory activity on SNARE complex formation. J Biol Chem 2009; 284:12480-90. [PMID: 19258327 DOI: 10.1074/jbc.m807182200] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Neurotransmitter release from presynaptic nerve terminals is regulated by SNARE complex-mediated synaptic vesicle fusion. Tomosyn, a negative regulator of neurotransmitter release, which is composed of N-terminal WD40 repeats, a tail domain, and a C-terminal VAMP-like domain, is known to inhibit SNARE complex formation by sequestering target SNAREs (t-SNAREs) upon interaction of its C-terminal VAMP-like domain with t-SNAREs. However, it remains unclear how the inhibitory activity of tomosyn is regulated. Here we show that the tail domain functions as a regulator of the inhibitory activity of tomosyn through intramolecular interactions. The binding of the tail domain to the C-terminal VAMP-like domain interfered with the interaction of the C-terminal VAMP-like domain with t-SNAREs, and thereby repressed the inhibitory activity of tomosyn on the SNARE complex formation. The repressed inhibitory activity of tomosyn was restored by the binding of the tail domain to the N-terminal WD40 repeats. These results indicate that the probable conformational change of tomosyn mediated by the intramolecular interactions of the tail domain controls its inhibitory activity on the SNARE complex formation, leading to a regulated inhibition of neurotransmitter release.
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Affiliation(s)
- Yasunori Yamamoto
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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25
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Abstract
The neoplastic tumour suppressors, Scribble, Dlg and Lgl, originally discovered in the vinegar fly Drosophila melanogaster, are currently being actively studied for their potential role in mammalian tumourigenesis. In Drosophila, these tumour suppressors function in a common genetic pathway to regulate apicobasal cell polarity and also play important roles in the control of cell proliferation, survival, differentiation and in cell migration/invasion. The precise mechanism by which Scribble, Dlg and Lgl function is not clear; however, they have been implicated in the regulation of signalling pathways, vesicle trafficking and in the Myosin II-actin cytoskeleton. We review the evidence for the involvement of Scribble, Dlg, and Lgl in cancer, and how the various functions ascribed to these tumour suppressors in Drosophila and mammalian systems may impact on the process of tumourigenesis.
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26
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Sakisaka T, Yamamoto Y, Mochida S, Nakamura M, Nishikawa K, Ishizaki H, Okamoto-Tanaka M, Miyoshi J, Fujiyoshi Y, Manabe T, Takai Y. Dual inhibition of SNARE complex formation by tomosyn ensures controlled neurotransmitter release. ACTA ACUST UNITED AC 2008; 183:323-37. [PMID: 18936251 PMCID: PMC2568027 DOI: 10.1083/jcb.200805150] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Neurotransmitter release from presynaptic nerve terminals is regulated by soluble NSF attachment protein receptor (SNARE) complex–mediated synaptic vesicle fusion. Tomosyn inhibits SNARE complex formation and neurotransmitter release by sequestering syntaxin-1 through its C-terminal vesicle-associated membrane protein (VAMP)–like domain (VLD). However, in tomosyn-deficient mice, the SNARE complex formation is unexpectedly decreased. In this study, we demonstrate that the N-terminal WD-40 repeat domain of tomosyn catalyzes the oligomerization of the SNARE complex. Microinjection of the tomosyn N-terminal WD-40 repeat domain into neurons prevented stimulated acetylcholine release. Thus, tomosyn inhibits neurotransmitter release by catalyzing oligomerization of the SNARE complex through the N-terminal WD-40 repeat domain in addition to the inhibitory activity of the C-terminal VLD.
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Affiliation(s)
- Toshiaki Sakisaka
- Division of Membrane Dynamics, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0017, Japan
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27
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Functional involvement of human discs large tumor suppressor in cytokinesis. Exp Cell Res 2008; 314:3118-29. [PMID: 18760273 DOI: 10.1016/j.yexcr.2008.07.032] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2008] [Revised: 07/25/2008] [Accepted: 07/30/2008] [Indexed: 01/07/2023]
Abstract
Cytokinesis is the final step of cell division that completes the separation of two daughter cells. We found that the human discs large (hDlg) tumor suppressor homologue is functionally involved in cytokinesis. The guanylate kinase (GUK) domain of hDlg mediates the localization of hDlg to the midbody during cytokinesis, and over-expression of the GUK domain in U2OS and HeLa cells impaired cytokinesis. Mouse embryonic fibroblasts (MEFs) derived from dlg mutant mice contained an increased number of multinucleated cells and showed reduced proliferation in culture. A kinesin-like motor protein, GAKIN, which binds directly to the GUK domain of hDlg, exhibited a similar intracellular distribution pattern with hDlg throughout mitosis and localized to the midbody during cytokinesis. However, the targeting of hDlg and GAKIN to the midbody appeared to be independent of each other. The midbody localization of GAKIN required its functional kinesin-motor domain. Treatment of cells with the siRNA specific for hDlg and GAKIN caused formation of multinucleated cells and delayed cytokinesis. Together, these results suggest that hDlg and GAKIN play functional roles in the maintenance of midbody architecture during cytokinesis.
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28
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An N, Blumer JB, Bernard ML, Lanier SM. The PDZ and band 4.1 containing protein Frmpd1 regulates the subcellular location of activator of G-protein signaling 3 and its interaction with G-proteins. J Biol Chem 2008; 283:24718-28. [PMID: 18566450 DOI: 10.1074/jbc.m803497200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Activator of G-protein signaling 3 (AGS3) is one of nine mammalian proteins containing one or more G-protein regulatory (GPR) motifs that stabilize the GDP-bound conformation of Galphai. Such proteins have revealed unexpected functional diversity for the "G-switch" in the control of events within the cell independent of the role of heterotrimeric G-proteins as transducers for G-protein-coupled receptors at the cell surface. A key question regarding this class of proteins is what controls their subcellular positioning and interaction with G-proteins. We conducted a series of yeast two-hybrid screens to identify proteins interacting with the tetratricopeptide repeat (TPR) of AGS3, which plays an important role in subcellular positioning of the protein. We report the identification of Frmpd1 (FERM and PDZ domain containing 1) as a regulatory binding partner of AGS3. Frmpd1 binds to the TPR domain of AGS3 and coimmunoprecipitates with AGS3 from cell lysates. Cell fractionation indicated that Frmpd1 stabilizes AGS3 in a membrane fraction. Upon cotransfection of COS7 cells with Frmpd1-GFP and AGS3-mRFP, AGS3-mRFP is observed in regions of the cell cortex and also in membrane extensions or processes where it appears to be colocalized with Frmpd1-GFP based upon the merged fluorescent signals. Frmpd1 knockdown (siRNA) in Cath.a-differentiated neuronal cells decreased the level of endogenous AGS3 in membrane fractions by approximately 50% and enhanced the alpha2-adrenergic receptor-mediated inhibition of forskolin-induced increases in cAMP. The coimmunoprecipitation of Frmpd1 with AGS3 is lost as the amount of Galphai3 in the cell is increased and AGS3 apparently switches its binding partner from Frmpd1 to Galphai3 indicating that the interaction of AGS3 with Frmpd1 and Galphai3 is mutually exclusive. Mechanistically, Frmpd1 may position AGS3 in a membrane environment where it then interacts with Galphai in a regulated manner.
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Affiliation(s)
- Ningfei An
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, Louisiana 70112, USA
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29
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Hensen EF, De Herdt MJ, Goeman JJ, Oosting J, Smit VT, Cornelisse CJ, Baatenburg de Jong RJ. Gene-expression of metastasized versus non-metastasized primary head and neck squamous cell carcinomas: a pathway-based analysis. BMC Cancer 2008; 8:168. [PMID: 18544165 PMCID: PMC2438367 DOI: 10.1186/1471-2407-8-168] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2007] [Accepted: 06/10/2008] [Indexed: 12/24/2022] Open
Abstract
Background Regional lymph node metastasis is an important prognostic factor in head and neck squamous cell carcinoma (HNSCC) and plays a decisive role in the choice of treatment. Here, we present an independent gene expression validation study of metastasized versus non-metastasized HNSCC. Methods We used a dataset recently published by Roepman et al. as reference dataset and an independent gene expression dataset of 11 metastasized and 11 non-metastasized HNSCC tumors as validation dataset. Reference and validation studies were performed on different microarray platforms with different probe sets and probe content. In addition to a supervised gene-based analysis, a supervised pathway-based analysis was performed, evaluating differences in gene expression for predefined tumorigenesis- and metastasis related gene sets. Results The gene-based analysis showed 26 significant differentially expressed genes in the reference dataset, 21 of which were present on the microarray platform used in the validation study. 7 of these genes appeared to be significantly expressed in the validation dataset, but failed to pass the correction for multiple testing. The pathway-based analysis revealed 23 significant differentially expressed gene sets, 7 of which were statistically validated. These gene sets are involved in extracellular matrix remodeling (MMPs, MMP regulating pathways and the uPA system), hypoxia and angiogenesis (HIF1α regulated angiogenic factors and HIF1α regulated invasion). Conclusion Pathways that are differentially expressed between metastasized and non-metastasized HNSCC are involved in the processes of extracellular matrix remodeling, hypoxia and angiogenesis. A supervised pathway-based analysis enhances the understanding of the biological context of the results, the comparability of results across different microarray studies, and reduces multiple testing problems by focusing on a limited number of pathways of interest instead of analyzing the large number of probes available on the microarray.
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Affiliation(s)
- Erik F Hensen
- Department of Otolaryngology and Head and Neck Surgery, Leiden University, Medical Centre, Leiden, The Netherlands.
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30
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Cloning and characterization of the promoter of Hugl-2, the human homologue of Drosophila lethal giant larvae (lgl) polarity gene. Biochem Biophys Res Commun 2008; 366:1067-73. [DOI: 10.1016/j.bbrc.2007.12.084] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Accepted: 12/14/2007] [Indexed: 11/21/2022]
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31
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Kaji N, Muramoto A, Mizuno K. LIM kinase-mediated cofilin phosphorylation during mitosis is required for precise spindle positioning. J Biol Chem 2007; 283:4983-92. [PMID: 18079118 DOI: 10.1074/jbc.m708644200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The interaction of astral microtubules with cortical actin networks is essential for the correct orientation of the mitotic spindle; however, little is known about how the cortical actin organization is regulated during mitosis. LIM kinase-1 (LIMK1) regulates actin dynamics by phosphorylating and inactivating cofilin, an actin-depolymerizing protein. LIMK1 activity increases during mitosis. Here we show that mitotic LIMK1 activation is critical for accurate spindle orientation in mammalian cells. Knockdown of LIMK1 suppressed a mitosis-specific increase in cofilin phosphorylation and caused unusual cofilin localization in the cell cortex in metaphase, instability of cortical actin organization and astral microtubules, irregular rotation and misorientation of the spindle, and a delay in anaphase onset. Similar results were obtained by treating the cells with a LIMK1 in hibitor peptide or latrunculin A or by overexpressing a non-phosphorylatable cofilin(S3A) mutant. Furthermore, localization of LGN (a protein containing the repetitive Leu-Gly-Asn tripeptide motifs), an important regulator of spindle orientation, in the crescent-shaped cortical regions was perturbed in LIMK1 knockdown cells. Our results suggest that LIMK1-mediated cofilin phosphorylation is required for accurate spindle orientation by stabilizing cortical actin networks during mitosis.
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Affiliation(s)
- Noriko Kaji
- Department of Biomolecular Sciences, Graduate School of Life Sciences, Tohoku University, Sendai, Miyagi 980-8578, Japan
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32
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Bialucha CU, Ferber EC, Pichaud F, Peak-Chew SY, Fujita Y. p32 is a novel mammalian Lgl binding protein that enhances the activity of protein kinase Czeta and regulates cell polarity. ACTA ACUST UNITED AC 2007; 178:575-81. [PMID: 17682048 PMCID: PMC2064465 DOI: 10.1083/jcb.200612022] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Lgl (lethal giant larvae) plays an important role in cell polarity. Atypical protein kinase C (aPKC) binds to and phosphorylates Lgl, and the phosphorylation negatively regulates Lgl activity. In this study, we identify p32 as a novel Lgl binding protein that directly binds to a domain on mammalian Lgl2 (mLgl2), which contains the aPKC phosphorylation site. p32 also binds to PKCζ, and the three proteins form a transient ternary complex. When p32 is bound, PKCζ is stimulated to phosphorylate mLgl2 more efficiently. p32 overexpression in Madin–Darby canine kidney cells cultured in a 3D matrix induces an expansion of the actin-enriched apical membrane domain and disrupts cell polarity. Addition of PKCζ inhibitor blocks apical actin accumulation, which is rescued by p32 overexpression. p32 knockdown by short hairpin RNA also induces cell polarity defects. Collectively, our data indicate that p32 is a novel regulator of cell polarity that forms a complex with mLgl2 and aPKC and enhances aPKC activity.
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Affiliation(s)
- Carl U Bialucha
- Medical Research Council Laboratory for Molecular Cell Biology and Cell Biology Unit, Department of Anatomy and Developmental Biology, University College London, London WC1E 6BT, England, UK
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Abstract
The mitotic spindle is the cellular scaffold that facilitates proper segregation of genetic material during cell division. Far from being static, the spindle is a dynamically regulated tool that can alter its size, shape and position during mitosis. Work in both insect and vertebrate systems has shown that regulation of this structure involves an array of highly conserved proteins. Moreover, it is now clear that tight regulation of the spindle during the process of neurogenesis is paramount to proper cell division and generation of the nervous system as a whole.
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Affiliation(s)
- Joshua J Buchman
- Department of Brain and Cognitive Sciences, Picower Institute for Learning and Memory, RIKEN-MIT Neuroscience Research Center, Howard Hughes Medical Institute, Cambridge, Massachusetts, USA
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Palti Y, Rodriguez MF, Gahr SA, Hansen JD. Evolutionary history of the ABCB2 genomic region in teleosts. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2007; 31:483-98. [PMID: 17055577 DOI: 10.1016/j.dci.2006.07.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2006] [Revised: 07/21/2006] [Accepted: 07/23/2006] [Indexed: 05/12/2023]
Abstract
Gene duplication, silencing and translocation have all been implicated in shaping the unique genomic architecture of the teleost MH regions. Previously, we demonstrated that trout possess five unlinked regions encoding MH genes. One of these regions harbors ABCB2 which in all other vertebrate classes is found in the MHC class II region. In this study, we sequenced a BAC contig for the trout ABCB2 region. Analysis of this region revealed the presence of genes homologous to those located in the human class II (ABCB2, BRD2, psiDAA), extended class II (RGL2, PHF1, SYGP1) and class III (PBX2, Notch-L) regions. The organization and syntenic relationships of this region were then compared to similar regions in humans, Tetraodon and zebrafish to learn more about the evolutionary history of this region. Our analysis indicates that this region was generated during the teleost-specific duplication event while also providing insight about potential MH paralogous regions in teleosts.
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Affiliation(s)
- Y Palti
- National Center for Cool and Cold Water Aquaculture USDA/ARS, 11861 Leetown Road, Kearneysville, WV 25430, USA.
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Voronina E, Wessel GM. Activator of G-protein signaling in asymmetric cell divisions of the sea urchin embryo. Dev Growth Differ 2006; 48:549-57. [PMID: 17118010 DOI: 10.1111/j.1440-169x.2006.00895.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
An asymmetric fourth cell division in the sea urchin embryo results in formation of daughter cells, macromeres and micromeres, with distinct sizes and fates. Several lines of functional evidence presented here, including pharmacological interference and dominant negative protein expression, indicate that heterotrimeric G protein Gi and its interaction partner, activator of G-protein signaling (AGS), are necessary for this asymmetric cell division. Inhibition of Gi signaling by pertussis toxin interferes with micromere formation and leads to defects in embryogenesis. AGS was isolated in a yeast two-hybrid screen with G alpha i as bait and was expressed in embryos localized to the cell cortex at the time of asymmetric divisions. Introduction of exogenous dominant-negative AGS protein, containing only G-protein regulatory (GPR) domains, selectively prevented the asymmetric division in normal micromere formation. These results support the growing evidence that AGS is a universal regulator of asymmetric cell divisions in embryos.
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Affiliation(s)
- Ekaterina Voronina
- Department of Molecular and Cell Biology and Biochemistry, Brown University, Providence, Rhode Island 02912, USA
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Blumer JB, Smrcka AV, Lanier S. Mechanistic pathways and biological roles for receptor-independent activators of G-protein signaling. Pharmacol Ther 2006; 113:488-506. [PMID: 17240454 PMCID: PMC1978177 DOI: 10.1016/j.pharmthera.2006.11.001] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2006] [Accepted: 11/10/2006] [Indexed: 01/14/2023]
Abstract
Signal processing via heterotrimeric G-proteins in response to cell surface receptors is a central and much investigated aspect of how cells integrate cellular stimuli to produce coordinated biological responses. The system is a target of numerous therapeutic agents and plays an important role in adaptive processes of organs; aberrant processing of signals through these transducing systems is a component of various disease states. In addition to G-protein coupled receptor (GPCR)-mediated activation of G-protein signaling, nature has evolved creative ways to manipulate and utilize the Galphabetagamma heterotrimer or Galpha and Gbetagamma subunits independent of the cell surface receptor stimuli. In such situations, the G-protein subunits (Galpha and Gbetagamma) may actually be complexed with alternative binding partners independent of the typical heterotrimeric Galphabetagamma. Such regulatory accessory proteins include the family of regulator of G-protein signaling (RGS) proteins that accelerate the GTPase activity of Galpha and various entities that influence nucleotide binding properties and/or subunit interaction. The latter group of proteins includes receptor-independent activators of G-protein signaling (AGS) proteins that play surprising roles in signal processing. This review provides an overview of our current knowledge regarding AGS proteins. AGS proteins are indicative of a growing number of accessory proteins that influence signal propagation, facilitate cross talk between various types of signaling pathways, and provide a platform for diverse functions of both the heterotrimeric Galphabetagamma and the individual Galpha and Gbetagamma subunits.
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Affiliation(s)
| | - Alan V. Smrcka
- Department of Pharmacology and Physiology, University of Rochester School of Medicine and Dentistry, 601 Elmwood Ave, Box 711, Rochester, NY 14642-8711
| | - S.M. Lanier
- ** Corresponding Author, Stephen M. Lanier, Ph.D., Department of Pharmacology, Medical University of South Carolina, Colcock Hall, 2nd Floor, PO Box 250002, 179 Ashley Avenue, Charleston, SC 29425, 843-792-0442, E-mail:
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Abstract
Cell polarity is one of the most basic properties of all normal cells and loss of polarity is a hallmark of cancer. While multiple proteins have been implicated in the maintenance of cell polarity, the functionally related neoplastic tumor suppressors Lethal giant larvae (Lgl), Scribble and Disks large comprise a unique group of molecules that are not only involved in the maintenance of cell polarity, but also in the regulation of cell proliferation and cancer. Lgl is the first identified member of this group. Loss of Lgl leads to massive tissue disorganization, tumor-like growth and lethal phenotypes in both Drosophila and mice. Lgl mutant cells display disruption of cell polarity, failure of asymmetric cell division, deregulation of Notch signaling and loss of proper cell fate determination. Lgl is a critical downstream target of the Par6/aPKC cell polarity complex; however, the functional role of Lgl itself and, specifically, the mechanisms of Lgl function in cell polarity and regulation of cell proliferation remain enigmatic. This minireview summarizes available information and discusses potential mechanisms of Lgl function.
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Affiliation(s)
- Valeri Vasioukhin
- Division of Human Biology, Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
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Abstract
Accessory proteins involved in signal processing through heterotrimeric G proteins are generally defined as proteins distinct from G protein-coupled receptor (GPCR), G protein, or classical effectors that regulate the strength/efficiency/specificity of signal transfer upon receptor activation or position these entities in the right microenvironment, contributing to the formation of a functional signal transduction complex. A flurry of recent studies have implicated an additional class of accessory proteins for this system that provide signal input to heterotrimeric G proteins in the absence of a cell surface receptor, serve as alternative binding partners for G protein subunits, provide unexpected modes of G protein regulation, and have introduced additional functional roles for G proteins. This group of accessory proteins includes the recently discovered Activators of G protein Signaling (AGS) proteins identified in a functional screen for receptor-independent activators of G protein signaling as well as several proteins identified in protein interaction screens and genetic screens in model organisms. These accessory proteins may influence GDP dissociation and nucleotide exchange at the G(alpha) subunit, alter subunit interactions within heterotrimeric G(alphabetagamma) independent of nucleotide exchange, or form complexes with G(alpha) or G(betagamma) independent of the typical G(alphabetagamma) heterotrimer. AGS and related accessory proteins reveal unexpected diversity in G protein subunits as signal transducers within the cell.
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Affiliation(s)
- Motohiko Sato
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, New Orleans, LA 70112, USA
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Baba T, Sakisaka T, Mochida S, Takai Y. PKA-catalyzed phosphorylation of tomosyn and its implication in Ca2+-dependent exocytosis of neurotransmitter. J Cell Biol 2005; 170:1113-25. [PMID: 16186257 PMCID: PMC2171531 DOI: 10.1083/jcb.200504055] [Citation(s) in RCA: 85] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2005] [Accepted: 08/22/2005] [Indexed: 12/24/2022] Open
Abstract
Neurotransmitter is released from nerve terminals by Ca2+-dependent exocytosis through many steps. SNARE proteins are key components at the priming and fusion steps, and the priming step is modulated by cAMP-dependent protein kinase (PKA), which causes synaptic plasticity. We show that the SNARE regulatory protein tomosyn is directly phosphorylated by PKA, which reduces its interaction with syntaxin-1 (a component of SNAREs) and enhances the formation of the SNARE complex. Electrophysiological studies using cultured superior cervical ganglion (SCG) neurons revealed that this enhanced formation of the SNARE complex by the PKA-catalyzed phosphorylation of tomosyn increased the fusion-competent readily releasable pool of synaptic vesicles and, thereby, enhanced neurotransmitter release. This mechanism was indeed involved in the facilitation of neurotransmitter release that was induced by a potent biological mediator, the pituitary adenylate cyclase-activating polypeptide, in SCG neurons. We describe the roles and modes of action of PKA and tomosyn in Ca2+-dependent neurotransmitter release.
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Affiliation(s)
- Takeshi Baba
- Department of Molecular Biology and Biochemistry, Osaka University Graduate School of Medicine/Faculty of Medicine, Suita 565-0871, Japan
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Kim YK, Kim YS, Baek KH. The WD-40 repeat motif of Lgl tumor suppressor proteins associated with salt tolerance and temperature sensitivity. Biochem Biophys Res Commun 2005; 331:922-8. [PMID: 15882966 DOI: 10.1016/j.bbrc.2005.04.017] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2005] [Indexed: 11/29/2022]
Abstract
We have recently identified mammalian homologues of lethal giant larvae (Lgl) tumor suppressor gene, rat Rgl-1 and bovine Bgl-1, and demonstrated that they can complement yeast double mutants lacking Sop1 and Sop2, yeast homologues of Lgl. These gene products are capable of regulating cellular viability in restrictive salt and temperature environments. Since Lgl family members contain the WD-40 repeat motif, we investigated its cellular functions using mouse homologue Mgl-1 in the absence of Sop1 and Sop2 in yeasts by complementation. Interestingly, mutant forms of Mgl-1 at the conserved glycine at position 450 and aspartic acid at position 453 in the most conserved WD-40 repeat motif were not able to complement, indicating that these amino acids are critical for regulating salt tolerance and temperature sensitivity in yeast. These results shed light on the important regulation of cytoskeletal complex for cellular polarity within eukaryotic cells.
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Affiliation(s)
- Yu-Kyung Kim
- Cell and Gene Therapy Research Institute, Graduate School of Life Science and Biotechnology, Pochon CHA University, CHA General Hospital, Seoul 135-081, Republic of Korea
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