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Gu QY, Liu YX, Wang JL, Huang XL, Li RN, Linghu H. LLGL2 Inhibits Ovarian Cancer Metastasis by Regulating Cytoskeleton Remodeling via ACTN1. Cancers (Basel) 2023; 15:5880. [PMID: 38136424 PMCID: PMC10742334 DOI: 10.3390/cancers15245880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 12/09/2023] [Accepted: 12/10/2023] [Indexed: 12/24/2023] Open
Abstract
Epithelial ovarian cancer is the most lethal gynecological malignant tumor. Although debulking surgery, chemotherapy, and PARP inhibitors have greatly improved survival, the prognosis for patients with advanced EOC without HRD is still poor. LLGL2, as a cell polarity factor, is involved in maintaining cell polarity and asymmetric cell division. In the study of zebrafish development, LLGL2 regulated the proliferation and migration of epidermal cells and the formation of cortical F-actin. However, the role of LLGL2 in ovarian cancer has not been described. Our study found, through bioinformatics analysis, that low expression of LLGL2 was significantly associated with a more advanced stage and a higher grade of EOC and a poorer survival of patients. Functional experiments that involved LLGL2 overexpression and knockdown showed that LLGL2 inhibited the migration and invasion abilities of ovarian cancer cells in vitro, without affecting their proliferation. LLGL2-overexpressing mice had fewer metastatic implant foci than the controls in vivo. Mechanistically, immunoprecipitation combined with mass spectrometry analysis suggested that LLGL2 regulated cytoskeletal remodeling by interacting with ACTN1. LLGL2 altered the intracellular localization and function of ACTN1 without changing its protein and mRNA levels. Collectively, we uncovered that LLGL2 impaired actin filament aggregation into bundles by interacting with ACTN1, which led to cytoskeleton remodeling and inhibition of the invasion and metastasis of ovarian cancer cells.
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Affiliation(s)
| | | | | | | | - Ruo-Nan Li
- Department of Gynecology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; (Q.-Y.G.); (Y.-X.L.); (J.-L.W.); (X.-L.H.)
| | - Hua Linghu
- Department of Gynecology, The First Affiliated Hospital of Chongqing Medical University, Chongqing 400016, China; (Q.-Y.G.); (Y.-X.L.); (J.-L.W.); (X.-L.H.)
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2
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Zhang M, Cao A, Lin L, Chen Y, Shang Y, Wang C, Zhang M, Zhu J. Phosphorylation-dependent recognition of diverse protein targets by the cryptic GK domain of MAGI MAGUKs. SCIENCE ADVANCES 2023; 9:eadf3295. [PMID: 37163606 PMCID: PMC10171801 DOI: 10.1126/sciadv.adf3295] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Dynamic signal transduction requires the rapid assembly and disassembly of signaling complexes, often mediated by phosphoprotein binding modules. The guanylate kinase-like (GK) domain of the membrane-associated guanylate kinases (MAGUKs) is such a module orchestrating signaling at cellular junctions. The MAGI subfamily of MAGUKs contains a truncated GK domain with unknown structure and function, although they participate in diverse physiological and pathological processes. Here, we demonstrate that the truncated GK domain of MAGI2 interacts with its adjacent PDZ0 domain to form a structural supramodule capable of recognizing phosphoproteins. A conserved phosphorylation-dependent binding motif for PDZ0-GK is delineated, which leads to identification of a set of previously unknown binding partners. We explore the structure and function of the MAGI2-target complex with an inhibitory peptide derived from the consensus motif. Our work reveals an action mechanism of the cryptic MAGI GKs and broadens our understanding of the target recognition rules of phosphoprotein binding modules.
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Affiliation(s)
- Meng Zhang
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
- Department of Neurology, the First Affiliated Hospital of USTC, Ministry of Education Key Laboratory for Cellular Dynamics, Biomedical Sciences and Health Laboratory of Anhui Province, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Aili Cao
- Department of Nephrology, Shanghai Sixth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200233, China
- Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China
| | - Lin Lin
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Ying Chen
- Department of Nephrology, Putuo Hospital, Shanghai University of Traditional Chinese Medicine, Shanghai 200062, China
| | - Yuan Shang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China
| | - Chao Wang
- Department of Neurology, the First Affiliated Hospital of USTC, Ministry of Education Key Laboratory for Cellular Dynamics, Biomedical Sciences and Health Laboratory of Anhui Province, School of Life Sciences, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei 230027, China
| | - Mingjie Zhang
- School of Life Sciences, Southern University of Science and Technology, Shenzhen 518055, China
| | - Jinwei Zhu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China
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3
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Xu Y, Jiang S, Hu Y, Zhang Q, Su W. TGF-β3 induces lactate production in Sertoli cell through inhibiting Notch pathway. Andrology 2022; 10:1644-1659. [PMID: 36057850 DOI: 10.1111/andr.13288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 11/29/2022]
Abstract
BACKGROUNDS In the testis, spermatocytes and spermatids rely on lactate produced by Sertoli cells (SCs) as energy source. TGF-β3 is one of the generally accepted paracrine regulatory factors of SC-created blood-testis barrier (BTB), yet its role in SC glycolysis and lactate production still remains unclear. OBJECTIVES To investigate the effect of TGF-β3 on glycolysis and lactate production in SCs and determine the role of Lgl2 and Notch signaling activity during this process. MATERIALS AND METHODS Primary cultured rat Sertoli cells and TM4 cells were treated with different concentrations of TGF-β3. In some experiments, cells were transfected with siRNA specifically targeting Lgl2 and then treated with TGF-β3 or DAPT. Lactate concentration, glucose and glutamine consumption in the culture medium, activity of PFK, LDH, and Gls, ATP level, oxygen consumption, extracellular acidification and mitochondrial respiration complex activity were detected using commercial kits. The protein level of Lgl2, LDH, MCT4, and activity of Akt, ERK, p38 MAPK, and Notch pathway were detected by Western blot. The stage-specific expression of Jagged1 was examined by immunohistochemistry and qPCR after LCM. Spermatogenesis in rat testis injected with recombinant Jagged1 (re-Jagged1) was observed by HE staining and lactate concentration in testis lysate was measured at different day point after re-Jagged1 treatment. RESULTS Significant enhancement of lactate concentration was detected in culture medium of both primary SCs and TM4 cells treated with TGF-β3 at 3 or 5 ng/ml. Besides, other parameters of glycolysis, i.e. glucose and Gln consumption, enzyme activity of PFK, LDH, and Gls, displayed different levels of increment in primary SCs and TM4 cells after TGF-β3 treatment. Mitochondria respiration of SCs was shown to decrease in response to TGF-β3. Lgl2, MCT4, activity of ERK and p38 MAPK were up-regulated, whereas Akt and Notch pathway activity were inhibited by TGF-β3. Silencing of Lgl2 in SCs affected lactate production and attenuated the above effects of TGF-β3 on SC glycolysis except for Gln consumption, Gls activity, and activity of Akt, ERK, and p38. DAPT treatment in SCs antagonized glycolysis suppression caused by Lgl2-silencing. In vivo analysis revealed a stage-specific expression of Jagged1 in contrary with TGF-β3. Activating Notch signaling by re-Jagged1 resulted in restorable hypospermatogenesis and lowered lactate level in rat testis. CONCLUSION TGF-β3 induces lactate production in Sertoli cell through upregulating Lgl2, which weakened the Notch signaling activity and intensified glycolysis in SCs. Thus, besides the known function of TGF-β3 as the BTB regulator, TGF-β3-Lgl2-Notch maybe considered as an important pathway controlling Sertoli cell glycolysis and spermatogenesis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Ying Xu
- Department of Biochemistry and Molecular Biology, College of Life Science, China Medical University, 77 Puhe Road, Shenbei New District, Shen Yang, 110122, China
| | - Shuyi Jiang
- Center of Reproductive Medicine, Shengjing Hospital of China Medical University, 36 SanHao Street, Shenhe District, Shenyang, 110004, China
| | - Ying Hu
- Department of Biochemistry and Molecular Biology, College of Life Science, China Medical University, 77 Puhe Road, Shenbei New District, Shen Yang, 110122, China
| | - Qiang Zhang
- Department of Biochemistry and Molecular Biology, College of Life Science, China Medical University, 77 Puhe Road, Shenbei New District, Shen Yang, 110122, China
| | - Wenhui Su
- Department of Biochemistry and Molecular Biology, College of Life Science, China Medical University, 77 Puhe Road, Shenbei New District, Shen Yang, 110122, China.,NHC Key Laboratory of Reproductive Health and Medical Genetics, Affiliated Reproductive Hospital of China Medical University, 10 Puhe Street, Huanggu District, Shenyang, 110084, China
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Khoury MJ, Bilder D. Minimal functional domains of the core polarity regulator Dlg. Biol Open 2022; 11:276053. [PMID: 35722710 PMCID: PMC9346270 DOI: 10.1242/bio.059408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 06/14/2022] [Indexed: 11/20/2022] Open
Abstract
The compartmentalized domains of polarized epithelial cells arise from mutually antagonistic actions between the apical Par complex and the basolateral Scrib module. In Drosophila, the Scrib module proteins Scribble (Scrib) and Discs-large (Dlg) are required to limit Lgl phosphorylation at the basolateral cortex, but how Scrib and Dlg could carry out such a ‘protection’ activity is not clear. We tested Protein Phosphatase 1α (PP1) as a potential mediator of this activity, but demonstrate that a significant component of Scrib and Dlg regulation of Lgl is PP1 independent, and found no evidence for a Scrib-Dlg-PP1 protein complex. However, the Dlg SH3 domain plays a role in Lgl protection and, in combination with the N-terminal region of the Dlg HOOK domain, in recruitment of Scrib to the membrane. We identify a ‘minimal Dlg’ comprised of the SH3 and HOOK domains that is both necessary and sufficient for Scrib localization and epithelial polarity function in vivo. This article has an associated First Person interview with the first author of the paper. Summary: A minimal SH3-HOOK fragment of Dlg is sufficient to support epithelial polarity through mechanisms independent of the PP1 phosphatase.
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Affiliation(s)
- Mark J Khoury
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley CA 94720, USA
| | - David Bilder
- Department of Molecular and Cell Biology, University of California-Berkeley, Berkeley CA 94720, USA
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Tian M, Li H, Yan X, Gu J, Zheng P, Luo S, Zhangsun D, Chen Q, Ouyang Q. Application of per-Residue Energy Decomposition to Design Peptide Inhibitors of PSD95 GK Domain. Front Mol Biosci 2022; 9:848353. [PMID: 35433833 PMCID: PMC9005747 DOI: 10.3389/fmolb.2022.848353] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 01/24/2022] [Indexed: 11/13/2022] Open
Abstract
Specific interaction between the postsynaptic density protein 95 (PSD95) and synapse-associated protein 90/postsynaptic density 95–associated protein (SAPAP) is crucial for excitatory synaptic development and plasticity. Designing inhibitors that target the guanylate kinase (GK) domain of PSD95, which is responsible for the interaction, is a promising manipulation tool for the investigation of the function of PSD95 GK and the etiology of its related psychiatric disorders. Herein, we designed new peptide inhibitors of PSD95 GK/SAPAP with higher binding affinity by using molecular dynamics simulations. First, the interactions between PSD95 GK and their reported phosphorylated and unphosphorylated peptides were explored by molecular dynamics simulations. Besides the hydrogen bonding interactions mediated by the phospho-serine (p-Ser) or corresponding phosphomimic residue Asp/Glu, the hydrophobic interactions from the other amino acids also contribute to the PSD95 GK/SAPAP interaction. As an unphosphorylated synthetic peptide with moderate binding affinity and relatively lower molecular weight, the QSF inhibitory peptide was selected for further modification. Based on per-residue energy decomposition results of the PSD95 GK/QSF complex, ten peptides were designed to enhance the binding interactions, especially the hydrophobic interactions. The top-ranked five peptides with lower binding energy were eventually synthesized. The binding affinities of the synthesized peptides were determined using fluorescence polarization (FP) assay. As expected, all peptides have higher binding affinity than the QSF peptide (Ki = 5.64 ± 0.51 μM). Among them, F10W was the most potent inhibitor (Ki = 0.75 ± 0.25 μM), suggesting that enhancement of the hydrophobic interactions is an important strategy for the design of new inhibitory peptides targeting PSD95 GK.
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Affiliation(s)
- Miao Tian
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Hongwei Li
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Xiao Yan
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Jing Gu
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Pengfei Zheng
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Sulan Luo
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, China
| | - Dongting Zhangsun
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, China
- *Correspondence: Dongting Zhangsun, ; Qiong Chen, ; Qin Ouyang,
| | - Qiong Chen
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
- *Correspondence: Dongting Zhangsun, ; Qiong Chen, ; Qin Ouyang,
| | - Qin Ouyang
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
- *Correspondence: Dongting Zhangsun, ; Qiong Chen, ; Qin Ouyang,
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Kroll JR, Remmelzwaal S, Boxem M. CeLINC, a fluorescence-based protein-protein interaction assay in Caenorhabditis elegans. Genetics 2021; 219:6380436. [PMID: 34849800 PMCID: PMC8664570 DOI: 10.1093/genetics/iyab163] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 09/22/2021] [Indexed: 11/30/2022] Open
Abstract
Interactions among proteins are fundamental for life and determining whether two particular proteins physically interact can be essential for fully understanding a protein’s function. We present Caenorhabditis elegans light-induced coclustering (CeLINC), an optical binary protein–protein interaction assay to determine whether two proteins interact in vivo. Based on CRY2/CIB1 light-dependent oligomerization, CeLINC can rapidly and unambiguously identify protein–protein interactions between pairs of fluorescently tagged proteins. A fluorescently tagged bait protein is captured using a nanobody directed against the fluorescent protein (GFP or mCherry) and brought into artificial clusters within the cell. Colocalization of a fluorescently tagged prey protein in the cluster indicates a protein interaction. We tested the system with an array of positive and negative reference protein pairs. Assay performance was extremely robust with no false positives detected in the negative reference pairs. We then used the system to test for interactions among apical and basolateral polarity regulators. We confirmed interactions seen between PAR-6, PKC-3, and PAR-3, but observed no physical interactions among the basolateral Scribble module proteins LET-413, DLG-1, and LGL-1. We have generated a plasmid toolkit that allows use of custom promoters or CRY2 variants to promote flexibility of the system. The CeLINC assay is a powerful and rapid technique that can be widely applied in C. elegans due to the universal plasmids that can be used with existing fluorescently tagged strains without need for additional cloning or genetic modification of the genome.
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Affiliation(s)
- Jason R Kroll
- Division of Developmental Biology, Department of Biology, Faculty of Science, Institute of Biodynamics and Biocomplexity, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Sanne Remmelzwaal
- Division of Developmental Biology, Department of Biology, Faculty of Science, Institute of Biodynamics and Biocomplexity, Utrecht University, 3584 CH Utrecht, the Netherlands
| | - Mike Boxem
- Division of Developmental Biology, Department of Biology, Faculty of Science, Institute of Biodynamics and Biocomplexity, Utrecht University, 3584 CH Utrecht, the Netherlands
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Unarta IC, Xu J, Shang Y, Cheung CHP, Zhu R, Chen X, Cao S, Cheung PPH, Bierer D, Zhang M, Huang X, Li X. Entropy of stapled peptide inhibitors in free state is the major contributor to the improvement of binding affinity with the GK domain. RSC Chem Biol 2021; 2:1274-1284. [PMID: 34458841 PMCID: PMC8341669 DOI: 10.1039/d1cb00087j] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/24/2021] [Indexed: 01/03/2023] Open
Abstract
Stapled peptides are promising protein–protein interaction (PPI) inhibitors that can increase the binding potency. Different from small-molecule inhibitors in which the binding mainly depends on energetic interactions with their protein targets, the binding of stapled peptides has long been suggested to be benefited from entropy. However, it remains challenging to reveal the molecular features that lead to this entropy gain, which could originate from the stabilization of the stapled peptide in solution or from the increased flexibility of the complex upon binding. This hinders the rational design of stapled peptides as PPI inhibitors. Using the guanylate kinase (GK) domain of the postsynaptic density protein 95 (PSD-95) as the target, we quantified the enthalpic and entropic contributions by combining isothermal titration calorimetry (ITC), X-ray crystallography, and free energy calculations based on all-atom molecular dynamics (MD) simulations. We successfully designed a stapled peptide inhibitor (staple 1) of the PSD-95 GK domain that led to a 25-fold increase in the binding affinity (from tens of μMs to 1.36 μM) with high cell permeability. We showed that entropy indeed greatly enhanced the binding affinity and the entropy gain was mainly due to the constrained-helix structure of the stapled peptide in solution (free state). Based on staple 1, we further designed two other stapled peptides (staple 2 and 3), which exerted even larger entropy gains compared to staple 1 because of their more flexible bound complexes (bound state). However, for staple 2 and 3, the overall binding affinities were not improved, as the loose binding in their bound states led to an enthalpic loss that largely compensated the excess entropy gain. Our work suggests that increasing the stability of the stapled peptide in free solution is an effective strategy for the rational design of stapled peptides as PPI inhibitors. The significant improvement in the binding affinity of the stapled peptide to the PSD-95 GK domain is mostly contributed by the reduction in the entropy penalty of the stapled peptide due to the restriction in the α-helical structure by stapling in the free state.![]()
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Affiliation(s)
- Ilona Christy Unarta
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay Kowloon Hong Kong .,Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong
| | - Jianchao Xu
- Department of Chemistry, State Key Lab of Synthetic Chemistry, The University of Hong Kong Hong Kong
| | - Yuan Shang
- Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong .,Division of Life Science, The Hong Kong University of Science and Technology Kowloon Hong Kong
| | - Carina Hey Pui Cheung
- Department of Chemistry, State Key Lab of Synthetic Chemistry, The University of Hong Kong Hong Kong
| | - Ruichi Zhu
- Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong .,Division of Life Science, The Hong Kong University of Science and Technology Kowloon Hong Kong
| | - Xudong Chen
- Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong .,Division of Life Science, The Hong Kong University of Science and Technology Kowloon Hong Kong
| | - Siqin Cao
- Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong .,Department of Chemistry, The Hong Kong University of Science and Technology Kowloon Hong Kong
| | - Peter Pak-Hang Cheung
- Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong .,Department of Chemistry, State Key Lab of Synthetic Chemistry, The University of Hong Kong Hong Kong
| | - Donald Bierer
- Department of Medicinal Chemistry, Bayer AG Aprather Weg 18A 42096 Wuppertal Germany
| | - Mingjie Zhang
- Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong .,Division of Life Science, The Hong Kong University of Science and Technology Kowloon Hong Kong
| | - Xuhui Huang
- Bioengineering Graduate Program, Department of Biological and Chemical Engineering, The Hong Kong University of Science and Technology, Clear Water Bay Kowloon Hong Kong .,Centre of Systems Biology and Human Health, State Key Laboratory of Molecular Neuroscience, The Hong Kong University of Science and Technology Clear Water Bay Kowloon Hong Kong .,Department of Chemistry, The Hong Kong University of Science and Technology Kowloon Hong Kong.,Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park Hong Kong
| | - Xuechen Li
- Department of Chemistry, State Key Lab of Synthetic Chemistry, The University of Hong Kong Hong Kong
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Nakajima YI. Scrib module proteins: Control of epithelial architecture and planar spindle orientation. Int J Biochem Cell Biol 2021; 136:106001. [PMID: 33962021 DOI: 10.1016/j.biocel.2021.106001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 01/15/2023]
Abstract
The Scrib module proteins, Scrib, Dlg, and Lgl, are conserved regulators of cell polarity in diverse biological contexts. Originally discovered as neoplastic tumor suppressors in the fruit fly Drosophila melanogaster, disruption of Scrib module components leads to tumorigenesis in mammalian epithelia and is associated with human cancers. With multiple protein interacting domains, Scrib module proteins function as determinants of basolateral identity in epithelial cells with apical-basal polarity while acting as signaling platform scaffold proteins. Recent studies have further revealed novel roles of the Scrib module in the control of epithelial architecture, ranging from polarity establishment and tricellular junction formation to planar spindle orientation during cell division. This review updates the current understanding of the molecular nature and physiological functions of the Scrib module with a focus on in vivo studies, providing a framework for how these protein dynamics affect the processes of epithelial organization.
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Affiliation(s)
- Yu-Ichiro Nakajima
- Frontier Research Institute for Interdisciplinary Sciences, Tohoku University, Sendai, Japan; Graduate School of Life Sciences, Tohoku University, Sendai, Japan.
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9
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Ventura G, Moreira S, Barros-Carvalho A, Osswald M, Morais-de-Sá E. Lgl cortical dynamics are independent of binding to the Scrib-Dlg complex but require Dlg-dependent restriction of aPKC. Development 2020; 147:dev.186593. [PMID: 32665243 DOI: 10.1242/dev.186593] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2019] [Accepted: 07/02/2020] [Indexed: 01/06/2023]
Abstract
Apical-basal polarity underpins the formation of epithelial barriers that are crucial for metazoan physiology. Although apical-basal polarity is long known to require the basolateral determinants Lethal Giant Larvae (Lgl), Discs Large (Dlg) and Scribble (Scrib), mechanistic understanding of their function is limited. Lgl plays a role as an aPKC inhibitor, but it remains unclear whether Lgl also forms complexes with Dlg or Scrib. Using fluorescence recovery after photobleaching, we show that Lgl does not form immobile complexes at the lateral domain of Drosophila follicle cells. Optogenetic depletion of plasma membrane PIP2 or dlg mutants accelerate Lgl cortical dynamics. However, Dlg and Scrib are required only for Lgl localization and dynamic behavior in the presence of aPKC function. Furthermore, light-induced oligomerization of basolateral proteins indicates that Lgl is not part of the Scrib-Dlg complex in the follicular epithelium. Thus, Scrib and Dlg are necessary to repress aPKC activity in the lateral domain but do not provide cortical binding sites for Lgl. Our work therefore highlights that Lgl does not act in a complex but in parallel with Scrib-Dlg to antagonize apical determinants.
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Affiliation(s)
- Guilherme Ventura
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Sofia Moreira
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - André Barros-Carvalho
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Mariana Osswald
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
| | - Eurico Morais-de-Sá
- i3S (Instituto de Investigação e Inovação em Saúde, Universidade do Porto) and IBMC (Instituto de Biologia Molecular e Celular), Rua Alfredo Allen, 208, 4200-135 Porto, Portugal
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10
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Abedrabbo M, Ravid S. Scribble, Lgl1, and myosin II form a complex in vivo to promote directed cell migration. Mol Biol Cell 2020; 31:2234-2248. [PMID: 32697665 PMCID: PMC7550706 DOI: 10.1091/mbc.e19-11-0657] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Scribble (Scrib) and Lethal giant larvae 1 (Lgl1) are conserved polarity proteins that play important roles in different forms of cell polarity. The roles of Scrib and Lgl1 in apical-basal cell polarity have been studied extensively, but little is known about their roles in the cell polarity of migrating cells. Furthermore, the effect of Scrib and Lgl1 interaction on cell polarity is largely unknown. In this study, we show that Scrib, through its leucine-rich repeat domain, forms a complex in vivo with Lgl1. Scrib also forms a complex with myosin II, and Scrib, Lgl1, and myosin II colocalize at the leading edge of migrating cells. The cellular localization and the cytoskeletal association of Scrib and Lgl1 are interdependent, as depletion of either protein affects its counterpart. In addition, depletion of either Scrib or Lgl1 disrupts the cellular localization of myosin II. We show that depletion of either Scrib or Lgl1 affects cell adhesion through the inhibition of focal adhesion disassembly. Finally, we show that Scrib and Lgl1 are required for proper cell polarity of migrating cells. These results provide new insights into the mechanism regulating the cell polarity of migrating cells by Scrib, Lgl1, and myosin II.
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Affiliation(s)
- Maha Abedrabbo
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
| | - Shoshana Ravid
- Department of Biochemistry and Molecular Biology, The Institute of Medical Research Israel-Canada, The Hebrew University-Hadassah Medical School, Jerusalem 91120, Israel
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11
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Jossin Y. Molecular mechanisms of cell polarity in a range of model systems and in migrating neurons. Mol Cell Neurosci 2020; 106:103503. [PMID: 32485296 DOI: 10.1016/j.mcn.2020.103503] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 04/20/2020] [Accepted: 05/23/2020] [Indexed: 01/09/2023] Open
Abstract
Cell polarity is defined as the asymmetric distribution of cellular components along an axis. Most cells, from the simplest single-cell organisms to highly specialized mammalian cells, are polarized and use similar mechanisms to generate and maintain polarity. Cell polarity is important for cells to migrate, form tissues, and coordinate activities. During development of the mammalian cerebral cortex, cell polarity is essential for neurogenesis and for the migration of newborn but as-yet undifferentiated neurons. These oriented migrations include both the radial migration of excitatory projection neurons and the tangential migration of inhibitory interneurons. In this review, I will first describe the development of the cerebral cortex, as revealed at the cellular level. I will then define the core molecular mechanisms - the Par/Crb/Scrib polarity complexes, small GTPases, the actin and microtubule cytoskeletons, and phosphoinositides/PI3K signaling - that are required for asymmetric cell division, apico-basal and front-rear polarity in model systems, including C elegans zygote, Drosophila embryos and cultured mammalian cells. As I go through each core mechanism I will explain what is known about its importance in radial and tangential migration in the developing mammalian cerebral cortex.
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Affiliation(s)
- Yves Jossin
- Laboratory of Mammalian Development & Cell Biology, Institute of Neuroscience, Université Catholique de Louvain, Brussels, Belgium.
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12
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Khoury MJ, Bilder D. Distinct activities of Scrib module proteins organize epithelial polarity. Proc Natl Acad Sci U S A 2020; 117:11531-11540. [PMID: 32414916 PMCID: PMC7260944 DOI: 10.1073/pnas.1918462117] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
A polarized architecture is central to both epithelial structure and function. In many cells, polarity involves mutual antagonism between the Par complex and the Scribble (Scrib) module. While molecular mechanisms underlying Par-mediated apical determination are well-understood, how Scrib module proteins specify the basolateral domain remains unknown. Here, we demonstrate dependent and independent activities of Scrib, Discs-large (Dlg), and Lethal giant larvae (Lgl) using the Drosophila follicle epithelium. Our data support a linear hierarchy for localization, but rule out previously proposed protein-protein interactions as essential for polarization. Cortical recruitment of Scrib does not require palmitoylation or polar phospholipid binding but instead an independent cortically stabilizing activity of Dlg. Scrib and Dlg do not directly antagonize atypical protein kinase C (aPKC), but may instead restrict aPKC localization by enabling the aPKC-inhibiting activity of Lgl. Importantly, while Scrib, Dlg, and Lgl are each required, all three together are not sufficient to antagonize the Par complex. Our data demonstrate previously unappreciated diversity of function within the Scrib module and begin to define the elusive molecular functions of Scrib and Dlg.
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Affiliation(s)
- Mark J Khoury
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
| | - David Bilder
- Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720
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13
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Zou Y. Breaking symmetry - cell polarity signaling pathways in growth cone guidance and synapse formation. Curr Opin Neurobiol 2020; 63:77-86. [PMID: 32361599 DOI: 10.1016/j.conb.2020.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 03/14/2020] [Accepted: 03/24/2020] [Indexed: 01/08/2023]
Abstract
Directional and positional information is essential for the diverse neuronal morphology and connectivity during development. The direction of axon growth is critical for building the correct networks among neurons, sometimes from far away. Neuronal synapses are asymmetric cell-cell junctions with distinct presynaptic and postsynaptic structures to convey neural activity in a directional fashion. Recent studies show that some of the key asymmetry is mediated by highly conversed cell polarity signaling pathways. These pathways, planar cell polarity and apical-basal polarity, are not required for the global axon-dendrite polarity. Therefore, the apparent distinct types of morphological asymmetry in the nervous system, growth cone turning and synaptic junctions, are mediated by similar cell polarity signaling mechanisms widely used in cellular and tissue morphogenesis.
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Affiliation(s)
- Yimin Zou
- Neurobiology Section, Biological Sciences Division, University of California, San Diego, CA 92093, United States.
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14
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Carmena A. The Case of the Scribble Polarity Module in Asymmetric Neuroblast Division in Development and Tumorigenesis. Int J Mol Sci 2020; 21:ijms21082865. [PMID: 32325951 PMCID: PMC7215838 DOI: 10.3390/ijms21082865] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 04/16/2020] [Accepted: 04/17/2020] [Indexed: 12/29/2022] Open
Abstract
The Scribble polarity module is composed by Scribble (Scrib), Discs large 1 (Dlg1) and Lethal (2) giant larvae (L(2)gl), a group of highly conserved neoplastic tumor suppressor genes (TSGs) from flies to humans. Even though the Scribble module has been profusely studied in epithelial cell polarity, the number of tissues and processes in which it is involved is increasingly growing. Here we discuss the role of the Scribble module in the asymmetric division of Drosophila neuroblasts (NBs), as well as the underlying mechanisms by which those TSGs act in this process. Finally, we also describe what we know about the consequences of mutating these genes in impairing the process of asymmetric NB division and promoting tumor-like overgrowth.
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Affiliation(s)
- Ana Carmena
- Instituto de Neurociencias, Consejo Superior de Investigaciones Científicas/Universidad Miguel Hernández, 03550 Sant Joan d'Alacant, Alicante, Spain
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15
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Zhang T, Cao G, Meng X, Ouyang C, Gao J, Sun Y, Wu J, Min Q, Zhang C, Zhang W. Lethal giant larvae 1 inhibits smooth muscle calcification via high mobility group box 1. J Mol Cell Cardiol 2020; 142:39-52. [PMID: 32268148 DOI: 10.1016/j.yjmcc.2020.03.017] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2019] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 02/05/2023]
Abstract
Vascular calcification is a pathological process closely related to atherosclerosis, diabetic vascular diseases, vascular injury, hypertension, chronic kidney disease and aging. Lethal giant larvae 1 (LGL1) is known as a key regulator of cell polarity and plays an important role in tumorigenesis. However, whether LGL1 regulates vascular calcification remains unclear. In this study, we generated smooth muscle-specific LGL1 knockout (LGL1SMKO) mice by cross-breeding LGL1flox/flox mice with α-SMA-Cre mice. LGL1 level was significantly decreased during calcifying conditions. Overexpression of LGL1 restrained high phosphate-induced calcification in vascular smooth muscle cells (VSMCs). Mechanically, LGL1 could bind with high mobility group box 1 (HMGB1) and promote its degradation via the lysosomal pathway, thereby inhibiting calcification. Smooth muscle-specific deletion of LGL1 increased HMGB1 level and aggravated vitamin D3-induced vascular calcification, which was attenuated by an HMGB1 inhibitor. LGL1 may inhibit vascular calcification by preventing osteogenic differentiation via promoting HMGB1 degradation.
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Affiliation(s)
- Tianran Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital of Shandong University, Jinan, China
| | - Guangqing Cao
- Department of Cardiovascular Surgery, Qilu Hospital of Shandong University, Jinan, Shandong, China
| | - Xiao Meng
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital of Shandong University, Jinan, China
| | - Changhan Ouyang
- School of Pharmacy, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Jiangang Gao
- School of Life Science and Key Laboratory of the Ministry of Education for Experimental Teratology, Shandong University, Jinan, China
| | - Yuanyuan Sun
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital of Shandong University, Jinan, China
| | - Jiliang Wu
- School of Pharmacy, Hubei University of Science and Technology, Xianning, Hubei, China
| | - Qing Min
- School of Pharmacy, Hubei University of Science and Technology, Xianning, Hubei, China.
| | - Cheng Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital of Shandong University, Jinan, China.
| | - Wencheng Zhang
- The Key Laboratory of Cardiovascular Remodeling and Function Research, Chinese Ministry of Education, Chinese National Health Commission and Chinese Academy of Medical Sciences, The State and Shandong Province Joint Key Laboratory of Translational Cardiovascular Medicine, Department of Cardiology, Qilu Hospital of Shandong University, Jinan, China; School of Pharmacy, Hubei University of Science and Technology, Xianning, Hubei, China.
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16
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Li H, Chen Q, Shan C, Guo C, Yang X, Chen Y, Zhu J, Ouyang Q. Characterizing the Binding Sites for GK Domain of DLG1 and DLG4 via Molecular Dynamics Simulation. Front Mol Biosci 2020; 7:1. [PMID: 32039235 PMCID: PMC6989407 DOI: 10.3389/fmolb.2020.00001] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 01/03/2020] [Indexed: 12/14/2022] Open
Abstract
Discs-large (DLG) is a member that belongs to the membrane-associated guanylate kinase (MAGUK) family. The GK domain of DLGs has evolved into a protein–protein interaction module that could bind with kinds of proteins to regulate diverse cellular functions. Previous reports have demonstrated the GK domain of DLGs functioned as a phosphor-peptide-binding module by resolving the crystal structures. Here we investigated into the interactions of DLG1 and DLG4 with their reported phosphor-peptides by molecular dynamics simulations. Post-dynamics analysis showed that DLG1/4 formed extensive interactions with phosphorylated ligands, including hydrophobic and hydrogen bonding interactions. Among them, the highly conserved residues among the DLGs in phosphor-site and β5 sheet were crucial for the binding according to the energy decomposition calculations. Additionally, the binding interactions between DLG4 and reported unphosphorylated peptides including MAP1A and designed GK inhibitory (GKI-QSF) peptides were analyzed. We found the key residues that played important roles in DLG4/unphosphorylated peptide systems were very similar as in DLG4/phosphor-peptide systems. Moreover, the molecular dynamic simulation for the complex of DLG1 and GKI-QSF was carried out and predicted that the GKI-QSF could bind with DLG1 with similar Kd value compared to DLG4/GKI-QSF, which was verified by using ITC assay (Kd = 1.20 ± 0.29 μM). Our study might be helpful for the better understanding of the structural and biological function of DLGs GK domain and encourage the discovery of new binders.
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Affiliation(s)
- Hongwei Li
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Qiong Chen
- Department of Neurology, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Changyu Shan
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Chunling Guo
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Xiuming Yang
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Yingchun Chen
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
| | - Jinwei Zhu
- Bio-X Institutes, Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Shanghai Jiao Tong University, Shanghai, China
| | - Qin Ouyang
- Department of Pharmaceutical Chemistry, Third Military Medical University, Chongqing, China
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17
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Janezic EM, Harris DA, Dinh D, Lee KS, Stewart A, Hinds TR, Hsu PL, Zheng N, Hague C. Scribble co-operatively binds multiple α 1D-adrenergic receptor C-terminal PDZ ligands. Sci Rep 2019; 9:14073. [PMID: 31575922 PMCID: PMC6773690 DOI: 10.1038/s41598-019-50671-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Accepted: 09/17/2019] [Indexed: 01/17/2023] Open
Abstract
Many G protein-coupled receptors (GPCRs) are organized as dynamic macromolecular complexes in human cells. Unraveling the structural determinants of unique GPCR complexes may identify unique protein:protein interfaces to be exploited for drug development. We previously reported α1D-adrenergic receptors (α1D-ARs) – key regulators of cardiovascular and central nervous system function – form homodimeric, modular PDZ protein complexes with cell-type specificity. Towards mapping α1D-AR complex architecture, biolayer interferometry (BLI) revealed the α1D-AR C-terminal PDZ ligand selectively binds the PDZ protein scribble (SCRIB) with >8x higher affinity than known interactors syntrophin, CASK and DLG1. Complementary in situ and in vitro assays revealed SCRIB PDZ domains 1 and 4 to be high affinity α1D-AR PDZ ligand interaction sites. SNAP-GST pull-down assays demonstrate SCRIB binds multiple α1D-AR PDZ ligands via a co-operative mechanism. Structure-function analyses pinpoint R1110PDZ4 as a unique, critical residue dictating SCRIB:α1D-AR binding specificity. The crystal structure of SCRIB PDZ4 R1110G predicts spatial shifts in the SCRIB PDZ4 carboxylate binding loop dictate α1D-AR binding specificity. Thus, the findings herein identify SCRIB PDZ domains 1 and 4 as high affinity α1D-AR interaction sites, and potential drug targets to treat diseases associated with aberrant α1D-AR signaling.
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Affiliation(s)
- Eric M Janezic
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Dorathy-Ann Harris
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Diana Dinh
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Kyung-Soon Lee
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Aaron Stewart
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Thomas R Hinds
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA
| | - Peter L Hsu
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA
| | - Ning Zheng
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.,Howard Hughes Medical Institute, University of Washington, Seattle, WA, 98195, USA
| | - Chris Hague
- Department of Pharmacology, School of Medicine, University of Washington, 1959 NE Pacific Street, Seattle, WA, 98195, USA.
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18
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Dealing with apical–basal polarity and intercellular junctions: a multidimensional challenge for epithelial cell division. Curr Opin Cell Biol 2019; 60:75-83. [DOI: 10.1016/j.ceb.2019.04.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 04/12/2019] [Accepted: 04/16/2019] [Indexed: 02/01/2023]
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19
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Peglion F, Goehring NW. Switching states: dynamic remodelling of polarity complexes as a toolkit for cell polarization. Curr Opin Cell Biol 2019; 60:121-130. [PMID: 31295650 PMCID: PMC6906085 DOI: 10.1016/j.ceb.2019.05.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2019] [Revised: 05/07/2019] [Accepted: 05/11/2019] [Indexed: 02/04/2023]
Abstract
Polarity is defined by the segregation of cellular components along a defined axis. To polarize robustly, cells must be able to break symmetry and subsequently amplify these nascent asymmetries. Finally, asymmetric localization of signaling molecules must be translated into functional regulation of downstream effector pathways. Central to these behaviors are a diverse set of cell polarity networks. Within these networks, molecules exhibit varied behaviors, dynamically switching among different complexes and states, active versus inactive, bound versus unbound, immobile versus diffusive. This ability to switch dynamically between states is intimately connected to the ability of molecules to generate asymmetric patterns within cells. Focusing primarily on polarity pathways governed by the conserved PAR proteins, we discuss strategies enabled by these dynamic behaviors that are used by cells to polarize. We highlight not only how switching between states is linked to the ability of polarity proteins to localize asymmetrically, but also how cells take advantage of 'state switching' to regulate polarity in time and space.
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Affiliation(s)
- Florent Peglion
- Cell Polarity, Migration and Cancer Unit, Institut Pasteur, UMR3691 CNRS, Equipe Labellisée Ligue Contre le Cancer, F-75015, Paris, France
| | - Nathan W Goehring
- The Francis Crick Institute, London, UK; MRC Laboratory for Molecular Cell Biology, UCL, London, UK.
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20
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New insights into apical-basal polarization in epithelia. Curr Opin Cell Biol 2019; 62:1-8. [PMID: 31505411 DOI: 10.1016/j.ceb.2019.07.017] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 07/25/2019] [Accepted: 07/26/2019] [Indexed: 11/21/2022]
Abstract
The establishment of an apical-basal axis of polarity is essential for the organization and functioning of epithelial cells. Polarization of epithelial cells is orchestrated by a network of conserved polarity regulators that establish opposing cortical domains through mutually antagonistic interactions and positive feedback loops. While our understanding is still far from complete, the molecular details behind these interactions continue to be worked out. Here, we highlight recent findings on the mechanisms that control the activity and localization of apical-basal polarity regulators, including oligomerization and higher-order complex formation, auto-inhibitory interactions, and electrostatic interactions with the plasma membrane.
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21
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Pickett MA, Naturale VF, Feldman JL. A Polarizing Issue: Diversity in the Mechanisms Underlying Apico-Basolateral Polarization In Vivo. Annu Rev Cell Dev Biol 2019; 35:285-308. [PMID: 31461314 DOI: 10.1146/annurev-cellbio-100818-125134] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Polarization along an apico-basolateral axis is a hallmark of epithelial cells and is essential for their selective barrier and transporter functions, as well as for their ability to provide mechanical resiliency to organs. Loss of polarity along this axis perturbs development and is associated with a wide number of diseases. We describe three steps involved in polarization: symmetry breaking, polarity establishment, and polarity maintenance. While the proteins involved in these processes are highly conserved among epithelial tissues and species, the execution of these steps varies widely and is context dependent. We review both theoretical principles underlying these steps and recent work demonstrating how apico-basolateral polarity is established in vivo in different tissues, highlighting how developmental and physiological contexts play major roles in the execution of the epithelial polarity program.
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Affiliation(s)
- Melissa A Pickett
- Department of Biology, Stanford University, Stanford, California 94305, USA;
| | - Victor F Naturale
- Department of Biology, Stanford University, Stanford, California 94305, USA;
| | - Jessica L Feldman
- Department of Biology, Stanford University, Stanford, California 94305, USA;
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22
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Ufimtsev IS, Almagor L, Weis WI, Levitt M. Solving the structure of Lgl2, a difficult blind test of unsupervised structure determination. Proc Natl Acad Sci U S A 2019; 116:10819-10823. [PMID: 31088964 PMCID: PMC6561170 DOI: 10.1073/pnas.1821513116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
In the companion paper by Ufimtsev and Levitt [Ufimtsev IS, Levitt M (2019) Proc Natl Acad Sci USA, 10.1073/pnas.1821512116], we presented a method for unsupervised solution of protein crystal structures and demonstrated its utility by solving several test cases of known structure in the 2.9- to 3.45-Å resolution range. Here we apply this method to solve the crystal structure of a 966-amino acid construct of human lethal giant larvae protein (Lgl2) that resisted years of structure determination efforts, at 3.2-Å resolution. The structure was determined starting with a molecular replacement (MR) model identified by unsupervised refinement of a pool of 50 candidate MR models. This initial model had 2.8-Å RMSD from the solution. The solved structure was validated by comparison with a model subsequently derived from an alternative crystal form diffracting to higher resolution. This model could phase an anomalous difference Fourier map from an Hg derivative, and a single-wavelength anomalous dispersion phased density map made from these sites aligned with the refined structure.
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Affiliation(s)
- Ivan S Ufimtsev
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
| | - Lior Almagor
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - William I Weis
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Molecular & Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305
| | - Michael Levitt
- Department of Structural Biology, Stanford University School of Medicine, Stanford, CA 94305;
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23
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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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24
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Casas-Tintó S, Ferrús A. Troponin-I mediates the localization of selected apico-basal cell polarity signaling proteins. J Cell Sci 2019; 132:jcs.225243. [PMID: 30872455 DOI: 10.1242/jcs.225243] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Accepted: 03/04/2019] [Indexed: 12/13/2022] Open
Abstract
Beyond its role in muscle contraction, Drosophila Troponin I (TnI; also known as Wings up A) is expressed in epithelial cells where it controls proliferation. TnI traffics between nucleus and cytoplasm through a sumoylation-dependent mechanism. We address here the role of TnI in the cytoplasm. TnI accumulates apically in epidermal cells and neuroblasts. TnI co-immunoprecipitates with Bazooka (also known as Par3) and Discs large (Dlg1, hereafter Dlg), two apico-basal polarity components. TnI depletion causes Baz and Dlg mislocalization; by contrast, the basolateral localization of Scribbled is not altered. In neuroblasts, TnI contributes to the polar localization of Miranda, while non-polar Dlg localization is not affected. Vertebrate phosphoinositide 3-kinase (PI3K) contributes to the apico-basal polarity of epithelia, but we find that Drosophila PI3K depletion alters neither the apical localization of TnI or Bazooka, nor the basal localization of Dlg. Nevertheless, overexpressing PI3K prevents the defects seen upon TnI depletion. TnI loss-of-function disrupts cytoskeletal β-Catenin, E-Cadherin and γ-Tubulin, and causes an increase in DNA damage, as revealed by analyzing γH2Av. We have previously shown that TnI depletion leads to apoptosis that can be suppressed by upregulating Sparc or downregulating Dronc. However, TnI-depleted cells expressing Sparc or downregulating Dronc, as well as those expressing p35 (also known as Cdk5α), that do not undergo apoptosis, still show DNA damage. This indicates that DNA damage is mechanistically independent of apoptosis induction. Thus, TnI binds certain apico-basal polarity signaling proteins in a cell type-dependent context, and this unveils a previously unsuspected diversity of mechanisms to allocate cell polarity factors.
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Affiliation(s)
- Sergio Casas-Tintó
- Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, C.S.I.C., Ave. Dr. Arce 37, Madrid 28002, Spain
| | - Alberto Ferrús
- Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, C.S.I.C., Ave. Dr. Arce 37, Madrid 28002, Spain
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25
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Hapak SM, Rothlin CV, Ghosh S. PAR3-PAR6-atypical PKC polarity complex proteins in neuronal polarization. Cell Mol Life Sci 2018; 75:2735-2761. [PMID: 29696344 PMCID: PMC11105418 DOI: 10.1007/s00018-018-2828-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Revised: 04/03/2018] [Accepted: 04/23/2018] [Indexed: 01/01/2023]
Abstract
Polarity is a fundamental feature of cells. Protein complexes, including the PAR3-PAR6-aPKC complex, have conserved roles in establishing polarity across a number of eukaryotic cell types. In neurons, polarity is evident as distinct axonal versus dendritic domains. The PAR3, PAR6, and aPKC proteins also play important roles in neuronal polarization. During this process, either aPKC kinase activity, the assembly of the PAR3-PAR6-aPKC complex or the localization of these proteins is regulated downstream of a number of signaling pathways. In turn, the PAR3, PAR6, and aPKC proteins control various effector molecules to establish neuronal polarity. Herein, we discuss the many signaling mechanisms and effector functions that have been linked to PAR3, PAR6, and aPKC during the establishment of neuronal polarity.
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Affiliation(s)
- Sophie M Hapak
- Department of Medicine, School of Medicine, University of Minnesota, 401 East River Parkway, Minneapolis, MN, 55455, USA.
| | - Carla V Rothlin
- Department of Immunobiology, School of Medicine, Yale University, 300 Cedar Street, New Haven, CT, 06520, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
| | - Sourav Ghosh
- Department of Neurology, School of Medicine, Yale University, 300 George Street, New Haven, CT, 06511, USA
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT, 06520, USA
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Hapak SM, Ghosh S, Rothlin CV. Axon Regeneration: Antagonistic Signaling Pairs in Neuronal Polarization. Trends Mol Med 2018; 24:615-629. [PMID: 29934283 DOI: 10.1016/j.molmed.2018.05.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Revised: 05/07/2018] [Accepted: 05/09/2018] [Indexed: 01/29/2023]
Abstract
Genome-wide screens, proteomics, and candidate-based approaches have identified numerous genes associated with neuronal regeneration following central nervous system (CNS) injury. Despite significant progress, functional recovery remains a challenge, even in model systems. Neuronal function depends on segregation of axonal versus dendritic domains. A key to functional recovery may lie in recapitulating the developmental signals that instruct axon specification and growth in adult neurons post-injury. Theoretically, binary activator-inhibitor elements operating as a Turing-like system within neurons can specify axonal versus dendritic domains and promote axon growth. We review here various molecules implicated in axon specification that function as signaling pairs driving neuronal polarization and axon growth.
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Affiliation(s)
- Sophie M Hapak
- Department of Medicine, School of Medicine, University of Minnesota, 401 East River Parkway, Minneapolis, MN 55455, USA
| | - Sourav Ghosh
- Department of Neurology, School of Medicine, Yale University, 300 George Street, New Haven, CT 06511, USA; Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT 06520, USA; Equal contribution.
| | - Carla V Rothlin
- Department of Pharmacology, School of Medicine, Yale University, 333 Cedar Street, New Haven, CT 06520, USA; Department of Immunobiology, School of Medicine, Yale University, 300 Cedar Street, New Haven, CT 06520, USA; Equal contribution.
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Stephens R, Lim K, Portela M, Kvansakul M, Humbert PO, Richardson HE. The Scribble Cell Polarity Module in the Regulation of Cell Signaling in Tissue Development and Tumorigenesis. J Mol Biol 2018; 430:3585-3612. [PMID: 29409995 DOI: 10.1016/j.jmb.2018.01.011] [Citation(s) in RCA: 91] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2017] [Revised: 01/19/2018] [Accepted: 01/19/2018] [Indexed: 01/22/2023]
Abstract
The Scribble cell polarity module, comprising Scribbled (Scrib), Discs-large (Dlg) and Lethal-2-giant larvae (Lgl), has a tumor suppressive role in mammalian epithelial cancers. The Scribble module proteins play key functions in the establishment and maintenance of different modes of cell polarity, as well as in the control of tissue growth, differentiation and directed cell migration, and therefore are major regulators of tissue development and homeostasis. Whilst molecular details are known regarding the roles of Scribble module proteins in cell polarity regulation, their precise mode of action in the regulation of other key cellular processes remains enigmatic. An accumulating body of evidence indicates that Scribble module proteins play scaffolding roles in the control of various signaling pathways, which are linked to the control of tissue growth, differentiation and cell migration. Multiple Scrib, Dlg and Lgl interacting proteins have been discovered, which are involved in diverse processes, however many function in the regulation of cellular signaling. Herein, we review the components of the Scrib, Dlg and Lgl protein interactomes, and focus on the mechanism by which they regulate cellular signaling pathways in metazoans, and how their disruption leads to cancer.
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Affiliation(s)
- Rebecca Stephens
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Krystle Lim
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Marta Portela
- Department of Molecular, Cellular and Developmental Neurobiology, Cajal Institute (CSIC), Avenida Doctor Arce, 37, Madrid 28002, Spain
| | - Marc Kvansakul
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Victoria, Australia
| | - Patrick O Humbert
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Victoria, Australia; Department of Biochemistry & Molecular Biology, University of Melbourne, Melbourne, Victoria 3010, Australia; Department of Pathology, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Helena E Richardson
- Department of Biochemistry and Genetics, La Trobe Institute of Molecular Science, La Trobe University, Melbourne, Victoria, Australia; Department of Biochemistry & Molecular Biology, University of Melbourne, Melbourne, Victoria 3010, Australia; Department of Anatomy & Neurobiology, University of Melbourne, Melbourne, Victoria 3010, Australia.
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Abstract
Selective enrichment of the polyphosphoinositides (PPIn), such as PtdIns(4,5)P2 and PtdIns4P, helps to determine the identity of the plasma membrane (PM) and regulates many aspects of cell biology through a vast number of protein effectors. Polarity proteins had long been assumed to be non-PPIn-binding proteins that mainly associate with PM/cell cortex through their extensive protein-protein interaction network. However, recent studies began to reveal that several key polarity proteins electrostatically bind to PPIn through their positively charged protein domains or structures and such PPIn-binding property is essential for their direct and specific attachment to PM. Although the physical nature of the charge-based PPIn binding appears to be simple and nonspecific, it serves as an elegant mechanism that can be efficiently and specifically regulated for achieving polarized PM targeting of polarity proteins. As an unexpected consequence, subcellular localization of PPIn-binding polarity proteins are also subject to regulations by physiological conditions such as hypoxia and ischemia that acutely and reversibly depletes PPIn from PM.
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Affiliation(s)
- Gerald R Hammond
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261
| | - Yang Hong
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, Pennsylvania 15261
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Zhu J, Zhou Q, Shang Y, Li H, Peng M, Ke X, Weng Z, Zhang R, Huang X, Li SS, Feng G, Lu Y, Zhang M. Synaptic Targeting and Function of SAPAPs Mediated by Phosphorylation-Dependent Binding to PSD-95 MAGUKs. Cell Rep 2017; 21:3781-3793. [DOI: 10.1016/j.celrep.2017.11.107] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 11/13/2017] [Accepted: 11/29/2017] [Indexed: 10/18/2022] Open
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Milgrom-Hoffman M, Humbert PO. Regulation of cellular and PCP signalling by the Scribble polarity module. Semin Cell Dev Biol 2017; 81:33-45. [PMID: 29154823 DOI: 10.1016/j.semcdb.2017.11.021] [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: 10/22/2017] [Revised: 11/11/2017] [Accepted: 11/13/2017] [Indexed: 10/18/2022]
Abstract
Since the first identification of the Scribble polarity module proteins as a new class of tumour suppressors that regulate both cell polarity and proliferation, an increasing amount of evidence has uncovered a broader role for Scribble, Dlg and Lgl in the control of fundamental cellular functions and their signalling pathways. Here, we review these findings as well as discuss more specifically the role of the Scribble module in PCP signalling.
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Affiliation(s)
- Michal Milgrom-Hoffman
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia
| | - Patrick O Humbert
- Department of Biochemistry & Genetics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria 3086, Australia; Department of Biochemistry & Molecular Biology, University of Melbourne, Melbourne, Victoria 3010, Australia; Department of Pathology, University of Melbourne, Melbourne, Victoria 3010, Australia.
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31
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Wen W, Zhang M. Protein Complex Assemblies in Epithelial Cell Polarity and Asymmetric Cell Division. J Mol Biol 2017; 430:3504-3520. [PMID: 28963071 DOI: 10.1016/j.jmb.2017.09.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2017] [Revised: 09/16/2017] [Accepted: 09/19/2017] [Indexed: 12/24/2022]
Abstract
Asymmetric local concentration of protein complexes on distinct membrane regions is a fundamental property in numerous biological processes and is a hallmark of cell polarity. Evolutionarily conserved core polarity proteins form specific and dynamic networks to regulate the establishment and maintenance of cell polarity, as well as distinct polarity-driven cellular events. This review focuses on the molecular and structural basis governing regulated formation of several sets of core cell polarity regulatory complexes, as well as their functions in epithelial cell polarization and asymmetric cell division.
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Affiliation(s)
- Wenyu Wen
- Department of Neurosurgery, Huashan Hospital, Institutes of Biomedical Sciences, Fudan University, Shanghai 200040, China; Key Laboratory of Metabolism and Molecular Medicine, Ministry of Education, Department of Systems Biology for Medicine, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai 200032, PR China.
| | - Mingjie Zhang
- Division of Life Science, State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China; Center of Systems Biology and Human Health, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong, China.
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Proteasome-independent polyubiquitin linkage regulates synapse scaffolding, efficacy, and plasticity. Proc Natl Acad Sci U S A 2017; 114:E8760-E8769. [PMID: 28973854 DOI: 10.1073/pnas.1620153114] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Ubiquitination-directed proteasomal degradation of synaptic proteins, presumably mediated by lysine 48 (K48) of ubiquitin, is a key mechanism in synapse and neural circuit remodeling. However, more than half of polyubiquitin (polyUb) species in the mammalian brain are estimated to be non-K48; among them, the most abundant is Lys 63 (K63)-linked polyUb chains that do not tag substrates for degradation but rather modify their properties and activity. Virtually nothing is known about the role of these nonproteolytic polyUb chains at the synapse. Here we report that K63-polyUb chains play a significant role in postsynaptic protein scaffolding and synaptic strength and plasticity. We found that the postsynaptic scaffold PSD-95 (postsynaptic density protein 95) undergoes K63 polyubiquitination, which markedly modifies PSD-95's scaffolding potentials, enables its synaptic targeting, and promotes synapse maturation and efficacy. TNF receptor-associated factor 6 (TRAF6) is identified as a direct E3 ligase for PSD-95, which, together with the E2 complex Ubc13/Uev1a, assembles K63-chains on PSD-95. In contrast, CYLD (cylindromatosis tumor-suppressor protein), a K63-specific deubiquitinase enriched in postsynaptic densities, cleaves K63-chains from PSD-95. We found that neuronal activity exerts potent control of global and synaptic K63-polyUb levels and, through NMDA receptors, drives rapid, CYLD-mediated PSD-95 deubiquitination, mobilizing and depleting PSD-95 from synapses. Silencing CYLD in hippocampal neurons abolishes NMDA-induced chemical long-term depression. Our results unveil a previously unsuspected role for nonproteolytic polyUb chains in the synapse and illustrate a mechanism by which a PSD-associated K63-linkage-specific ubiquitin machinery acts on a major postsynaptic scaffold to regulate synapse organization, function, and plasticity.
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Mechanisms of MAGUK-mediated cellular junctional complex organization. Curr Opin Struct Biol 2017; 48:6-15. [PMID: 28917202 DOI: 10.1016/j.sbi.2017.08.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2017] [Revised: 08/22/2017] [Accepted: 08/28/2017] [Indexed: 01/01/2023]
Abstract
Membrane-associated guanylate kinases (MAGUKs) are a family of scaffold proteins that are enriched in cellular junctions and essential for tissue development and homeostasis. Mutations of MAGUKs are linked to many human diseases including cancers, psychiatric disorders, and intellectual disabilities. MAGUKs share a common PDZ-SH3-GK tandem domain organization at the C-terminal end. In this review, we summarize the mechanistic basis governing target recognition and regulations of this binding by the PDZ-SH3-GK tandem of various MAGUKs. We also discuss recent discoveries showing unique folding features of MAGUK PDZ-SH3-GK tandems that facilitate ligand-induced oligomerization of MAGUKs and phase transition of MAGUK-assembled synaptic signaling complexes.
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Structure of the PSD-95/MAP1A complex reveals a unique target recognition mode of the MAGUK GK domain. Biochem J 2017; 474:2817-2828. [DOI: 10.1042/bcj20170356] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 07/02/2017] [Accepted: 07/12/2017] [Indexed: 01/06/2023]
Abstract
The PSD-95 family of membrane-associated guanylate kinases (MAGUKs) are major synaptic scaffold proteins and play crucial roles in the dynamic regulation of dendritic remodelling, which is understood to be the foundation of synaptogenesis and synaptic plasticity. The guanylate kinase (GK) domain of MAGUK family proteins functions as a phosphor-peptide binding module. However, the GK domain of PSD-95 has been found to directly bind to a peptide sequence within the C-terminal region of neuronal-specific microtubule-associated protein 1A (MAP1A), although the detailed molecular mechanism governing this phosphorylation-independent interaction at the atomic level is missing. In the present study, we determine the crystal structure of PSD-95 GK in complex with the MAP1A peptide at 2.6-Å resolution. The complex structure reveals that, unlike a linear and elongated conformation in the phosphor-peptide/GK complexes, the MAP1A peptide adopts a unique conformation with a stretch of hydrophobic residues far from each other in the primary sequence clustering and interacting with the ‘hydrophobic site’ of PSD-95 GK and a highly conserved aspartic acid of MAP1A (D2117) mimicking the phosphor-serine/threonine in binding to the ‘phosphor-site’ of PSD-95 GK. We demonstrate that the MAP1A peptide may undergo a conformational transition upon binding to PSD-95 GK. Further structural comparison of known DLG GK-mediated complexes reveals the target recognition specificity and versatility of DLG GKs.
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35
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Campanale JP, Sun TY, Montell DJ. Development and dynamics of cell polarity at a glance. J Cell Sci 2017; 130:1201-1207. [PMID: 28365593 DOI: 10.1242/jcs.188599] [Citation(s) in RCA: 118] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Cells exhibit morphological and molecular asymmetries that are broadly categorized as cell polarity. The cell polarity established in early embryos prefigures the macroscopic anatomical asymmetries characteristic of adult animals. For example, eggs and early embryos have polarized distributions of RNAs and proteins that generate global anterior/posterior and dorsal/ventral axes. The molecular programs that polarize embryos are subsequently reused in multiple contexts. Epithelial cells require apical/basal polarity to establish their barrier function. Migrating cells polarize in the direction of movement, creating distinct leading and trailing structures. Asymmetrically dividing stem cells partition different molecules between themselves and their daughter cells. Cell polarity can develop de novo, be maintained through rounds of cell division and be dynamically remodeled. In this Cell Science at a Glance review and poster, we describe molecular asymmetries that underlie cell polarity in several cellular contexts. We highlight multiple developmental systems that first establish cell/developmental polarity, and then maintain it. Our poster showcases repeated use of the Par, Scribble and Crumbs polarity complexes, which drive the development of cell polarity in many cell types and organisms. We then briefly discuss the diverse and dynamic changes in cell polarity that occur during cell migration, asymmetric cell division and in planar polarized tissues.
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Affiliation(s)
- Joseph P Campanale
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Thomas Y Sun
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
| | - Denise J Montell
- Department of Molecular, Cellular and Developmental Biology, University of California Santa Barbara, Santa Barbara, CA 93106, USA
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36
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Bergstralh DT, Dawney NS, St Johnston D. Spindle orientation: a question of complex positioning. Development 2017; 144:1137-1145. [DOI: 10.1242/dev.140764] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
The direction in which a cell divides is determined by the orientation of its mitotic spindle at metaphase. Spindle orientation is therefore important for a wide range of developmental processes, ranging from germline stem cell division to epithelial tissue homeostasis and regeneration. In multiple cell types in multiple animals, spindle orientation is controlled by a conserved biological machine that mediates a pulling force on astral microtubules. Restricting the localization of this machine to only specific regions of the cortex can thus determine how the mitotic spindle is oriented. As we review here, recent findings based on studies in tunicate, worm, fly and vertebrate cells have revealed that the mechanisms for mediating this restriction are surprisingly diverse.
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Affiliation(s)
- Dan T. Bergstralh
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Nicole S. Dawney
- Department of Biology, University of Rochester, Rochester, NY 14627, USA
| | - Daniel St Johnston
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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37
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Evaluation of Lethal Giant Larvae as a Schistosomiasis Vaccine Candidate. BIOMED RESEARCH INTERNATIONAL 2016; 2016:4680812. [PMID: 27957496 PMCID: PMC5120214 DOI: 10.1155/2016/4680812] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 07/20/2016] [Accepted: 08/11/2016] [Indexed: 01/07/2023]
Abstract
Schistosomiasis is a neglected tropical disease of humans, and it is considered to be the second most devastating parasitic disease after malaria. Eggs produced by normally developed female worms are important in the transmission of the parasite, and they responsible for the pathogenesis of schistosomiasis. The tumor suppressor gene lethal giant larvae (lgl) has an essential function in establishing apical-basal cell polarity, cell proliferation, differentiation, and tissue organization. In our earlier study, downregulation of the lgl gene induced a significant reduction in the egg hatching rate of Schistosoma japonicum (Sj) eggs. In this study, the Sjlgl gene was used as a vaccine candidate against schistosomiasis, and vaccination achieved and maintained a stable reduction of the egg hatching rate, which is consistent with previous studies, in addition to reducing the worm burden and liver egg burden in some trials.
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38
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Flores-Benitez D, Knust E. Dynamics of epithelial cell polarity in Drosophila: how to regulate the regulators? Curr Opin Cell Biol 2016; 42:13-21. [DOI: 10.1016/j.ceb.2016.03.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 03/25/2016] [Indexed: 10/22/2022]
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An Atypical MAGUK GK Target Recognition Mode Revealed by the Interaction between DLG and KIF13B. Structure 2016; 24:1876-1885. [PMID: 27642159 DOI: 10.1016/j.str.2016.08.008] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2016] [Revised: 07/14/2016] [Accepted: 08/04/2016] [Indexed: 01/19/2023]
Abstract
The membrane-associated guanylate kinase (MAGUK) scaffold proteins share a signature guanylate kinase (GK) domain. Despite their diverse functional roles in cell polarity control and synaptic signaling, the currently known mode of action of MAGUK GK is via its binding to phosphorylated short peptides from target proteins. Here, we discover that the GK domain of DLG MAGUK binds to an unphosphorylated and autonomously folded domain within the stalk region (MAGUK binding stalk [MBS] domain) of a kinesin motor KIF13B with high specificity and affinity. The structure of DLG4 GK in complex with KIF13B MBS reveals the molecular mechanism governing this atypical GK/target recognition mode and provides insights into DLG/KIF13B complex-mediated regulation of diverse cellular processes such as asymmetric cell division. We further show that binding to non-phosphorylated targets is another general property of MAGUK GKs, thus expanding the mechanisms of action of the MAGUK family proteins.
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40
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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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41
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Bergstralh DT, Lovegrove HE, Kujawiak I, Dawney NS, Zhu J, Cooper S, Zhang R, St Johnston D. Pins is not required for spindle orientation in the Drosophila wing disc. Development 2016; 143:2573-81. [PMID: 27287805 PMCID: PMC4958339 DOI: 10.1242/dev.135475] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 06/01/2016] [Indexed: 02/03/2023]
Abstract
In animal cells, mitotic spindles are oriented by the dynein/dynactin motor complex, which exerts a pulling force on astral microtubules. Dynein/dynactin localization depends on Mud/NUMA, which is typically recruited to the cortex by Pins/LGN. In Drosophila neuroblasts, the Inscuteable/Baz/Par-6/aPKC complex recruits Pins apically to induce vertical spindle orientation, whereas in epithelial cells Dlg recruits Pins laterally to orient the spindle horizontally. Here we investigate division orientation in the Drosophila imaginal wing disc epithelium. Live imaging reveals that spindle angles vary widely during prometaphase and metaphase, and therefore do not reliably predict division orientation. This finding prompted us to re-examine mutants that have been reported to disrupt division orientation in this tissue. Loss of Mud misorients divisions, but Inscuteable expression and aPKC, dlg and pins mutants have no effect. Furthermore, Mud localizes to the apical-lateral cortex of the wing epithelium independently of both Pins and cell cycle stage. Thus, Pins is not required in the wing disc because there are parallel mechanisms for Mud localization and hence spindle orientation, making it a more robust system than in other epithelia. Highlighted article: Mud (Drosophila NuMA), a crucial spindle orientation factor, does not require its binding partner Pins (Drosophila LGN) to localize or function in the Drosophila imaginal wing disc.
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Affiliation(s)
- Dan T Bergstralh
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Holly E Lovegrove
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Izabela Kujawiak
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Nicole S Dawney
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Jinwei Zhu
- National Center for Protein Science Shanghai, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Samantha Cooper
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
| | - Rongguang Zhang
- National Center for Protein Science Shanghai, Shanghai Institute of Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Daniel St Johnston
- The Gurdon Institute and the Department of Genetics, University of Cambridge, Tennis Court Road, Cambridge CB2 1QN, UK
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42
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Zhu J, Shang Y, Zhang M. Mechanistic basis of MAGUK-organized complexes in synaptic development and signalling. Nat Rev Neurosci 2016; 17:209-23. [DOI: 10.1038/nrn.2016.18] [Citation(s) in RCA: 130] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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43
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Dong W, Zhang X, Liu W, Chen YJ, Huang J, Austin E, Celotto AM, Jiang WZ, Palladino MJ, Jiang Y, Hammond GRV, Hong Y. A conserved polybasic domain mediates plasma membrane targeting of Lgl and its regulation by hypoxia. J Cell Biol 2015; 211:273-86. [PMID: 26483556 PMCID: PMC4621827 DOI: 10.1083/jcb.201503067] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Accepted: 09/02/2015] [Indexed: 01/01/2023] Open
Abstract
The plasma membrane targeting of Lgl, a key polarity and tumor suppressor protein, is mediated by electrostatic interactions between a polybasic motif in Lgl and phospholipids on the plasma membrane, and this mechanism is regulated by hypoxia and aPKC-phosphorylation. Lethal giant larvae (Lgl) plays essential and conserved functions in regulating both cell polarity and tumorigenesis in Drosophila melanogaster and vertebrates. It is well recognized that plasma membrane (PM) or cell cortex localization is crucial for Lgl function in vivo, but its membrane-targeting mechanisms remain poorly understood. Here, we discovered that hypoxia acutely and reversibly inhibits Lgl PM targeting through a posttranslational mechanism that is independent of the well-characterized atypical protein kinase C (aPKC) or Aurora kinase–mediated phosphorylations. Instead, we identified an evolutionarily conserved polybasic (PB) domain that targets Lgl to the PM via electrostatic binding to membrane phosphatidylinositol phosphates. Such PB domain–mediated PM targeting is inhibited by hypoxia, which reduces inositol phospholipid levels on the PM through adenosine triphosphate depletion. Moreover, Lgl PB domain contains all the identified phosphorylation sites of aPKC and Aurora kinases, providing a molecular mechanism by which phosphorylations neutralize the positive charges on the PB domain to inhibit Lgl PM targeting.
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Affiliation(s)
- Wei Dong
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Xuejing Zhang
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Weijie Liu
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Yi-jiun Chen
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Juan Huang
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261 Nanjing Medical University, Nanjing 210029, China
| | - Erin Austin
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Alicia M Celotto
- Department of Pharmacology & Chemical Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Wendy Z Jiang
- Department of Pharmacology & Chemical Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Michael J Palladino
- Department of Pharmacology & Chemical Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Yu Jiang
- Department of Pharmacology & Chemical Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Gerald R V Hammond
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
| | - Yang Hong
- Department of Cell Biology, University of Pittsburgh Medical School, Pittsburgh, PA 15261
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Nakajima YI, Gibson MC. Epithelial cell division: Aurora kicks Lgl to the cytoplasmic curb. Curr Biol 2015; 25:R43-5. [PMID: 25562301 DOI: 10.1016/j.cub.2014.11.052] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Drosophila neoplastic tumor suppressor Lethal giant larvae (Lgl) regulates apico-basal polarity in epithelia as well as the asymmetric segregation of cell fate in neural progenitors. Two new studies uncover a new facet of its regulation in epithelia, where Aurora-dependent phosphorylation triggers Lgl dissociation from the basolateral cortex to facilitate planar orientation of the mitotic spindle.
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Affiliation(s)
- Yu-ichiro Nakajima
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA
| | - Matthew C Gibson
- Stowers Institute for Medical Research, 1000 East 50th Street, Kansas City, MO 64110, USA; Department of Anatomy and Cell Biology, University of Kansas Medical Center 3901 Rainbow Boulevard, Kansas City, Kansas 66160, USA.
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Lin WH, Asmann YW, Anastasiadis PZ. Expression of polarity genes in human cancer. Cancer Inform 2015; 14:15-28. [PMID: 25991909 PMCID: PMC4390136 DOI: 10.4137/cin.s18964] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 02/10/2015] [Accepted: 02/12/2015] [Indexed: 01/01/2023] Open
Abstract
Polarity protein complexes are crucial for epithelial apical–basal polarity and directed cell migration. Since alterations of these processes are common in cancer, polarity proteins have been proposed to function as tumor suppressors or oncogenic promoters. Here, we review the current understanding of polarity protein functions in epithelial homeostasis, as well as tumor formation and progression. As most previous studies focused on the function of single polarity proteins in simplified model systems, we used a genomics approach to systematically examine and identify the expression profiles of polarity genes in human cancer. The expression profiles of polarity genes were distinct in different human tissues and classified cancer types. Additionally, polarity expression profiles correlated with disease progression and aggressiveness, as well as with identified cancer types, where specific polarity genes were commonly altered. In the case of Scribble, gene expression analysis indicated its common amplification and upregulation in human cancer, suggesting a tumor promoting function.
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Affiliation(s)
- Wan-Hsin Lin
- Department of Cancer Biology, Mayo Clinic, Jacksonville, FL, USA
| | - Yan W Asmann
- Department of Health Sciences Research, Mayo Clinic, Jacksonville, FL, USA
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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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Aurora kinases phosphorylate Lgl to induce mitotic spindle orientation in Drosophila epithelia. Curr Biol 2014; 25:61-8. [PMID: 25484300 PMCID: PMC4291145 DOI: 10.1016/j.cub.2014.10.052] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Revised: 09/22/2014] [Accepted: 10/21/2014] [Indexed: 11/23/2022]
Abstract
The Lethal giant larvae (Lgl) protein was discovered in Drosophila as a tumor suppressor in both neural stem cells (neuroblasts) and epithelia. In neuroblasts, Lgl relocalizes to the cytoplasm at mitosis, an event attributed to phosphorylation by mitotically activated aPKC kinase and thought to promote asymmetric cell division. Here we show that Lgl also relocalizes to the cytoplasm at mitosis in epithelial cells, which divide symmetrically. The Aurora A and B kinases directly phosphorylate Lgl to promote its mitotic relocalization, whereas aPKC kinase activity is required only for polarization of Lgl. A form of Lgl that is a substrate for aPKC, but not Aurora kinases, can restore cell polarity in lgl mutants but reveals defects in mitotic spindle orientation in epithelia. We propose that removal of Lgl from the plasma membrane at mitosis allows Pins/LGN to bind Dlg and thus orient the spindle in the plane of the epithelium. Our findings suggest a revised model for Lgl regulation and function in both symmetric and asymmetric cell divisions.
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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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Ngok SP, Lin WH, Anastasiadis PZ. Establishment of epithelial polarity--GEF who's minding the GAP? J Cell Sci 2014; 127:3205-15. [PMID: 24994932 DOI: 10.1242/jcs.153197] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Cell polarization is a fundamental process that underlies epithelial morphogenesis, cell motility, cell division and organogenesis. Loss of polarity predisposes tissues to developmental disorders and contributes to cancer progression. The formation and establishment of epithelial cell polarity is mediated by the cooperation of polarity protein complexes, namely the Crumbs, partitioning defective (Par) and Scribble complexes, with Rho family GTPases, including RhoA, Rac1 and Cdc42. The activation of different GTPases triggers distinct downstream signaling pathways to modulate protein-protein interactions and cytoskeletal remodeling. The spatio-temporal activation and inactivation of these small GTPases is tightly controlled by a complex interconnected network of different regulatory proteins, including guanine-nucleotide-exchange factors (GEFs), GTPase-activating proteins (GAPs), and guanine-nucleotide-dissociation inhibitors (GDIs). In this Commentary, we focus on current understanding on how polarity complexes interact with GEFs and GAPs to control the precise location and activation of Rho GTPases (Crumbs for RhoA, Par for Rac1, and Scribble for Cdc42) to promote apical-basal polarization in mammalian epithelial cells. The mutual exclusion of GTPase activities, especially that of RhoA and Rac1, which is well established, provides a mechanism through which polarity complexes that act through distinct Rho GTPases function as cellular rheostats to fine-tune specific downstream pathways to differentiate and preserve the apical and basolateral domains. This article is part of a Minifocus on Establishing polarity.
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Affiliation(s)
- Siu P Ngok
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Griffin Cancer Research Building, Room 307, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Wan-Hsin Lin
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Griffin Cancer Research Building, Room 307, 4500 San Pablo Road, Jacksonville, FL 32224, USA
| | - Panos Z Anastasiadis
- Department of Cancer Biology, Mayo Clinic Comprehensive Cancer Center, Griffin Cancer Research Building, Room 307, 4500 San Pablo Road, Jacksonville, FL 32224, USA
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