1
|
Davies DS, Arthur AT, Aitken HL, Crossett B, Goldsbury CS. Protein complexes from mouse and chick brain that interact with phospho-KXGS motif tau/microtubule associated protein antibody. Biol Open 2024; 13:bio060067. [PMID: 38299702 PMCID: PMC10924212 DOI: 10.1242/bio.060067] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Accepted: 01/29/2024] [Indexed: 02/02/2024] Open
Abstract
Mouse monoclonal 12E8 antibody, which recognises conserved serine phosphorylated KXGS motifs in the microtubule binding domains of tau/tau-like microtubule associated proteins (MAPs), shows elevated binding in brain during normal embryonic development (mammals and birds) and at the early stages of human Alzheimer's disease (AD). It also labels ADF/cofilin-actin rods that form in neurites during exposure to stressors. We aimed to identify direct and indirect 12E8 binding proteins in postnatal mouse brain and embryonic chick brain by immunoprecipitation (IP), mass spectrometry and immunofluorescence. Tau and/or MAP2 were major direct 12E8-binding proteins detected in all IPs, and actin and/or tubulin were co-immunoprecipitated in most samples. Additional proteins were different in mouse versus chick brain IP. In mouse brain IPs, FSD1l and intermediate filament proteins - vimentin, α-internexin, neurofilament polypeptides - were prominent. Immunofluorescence and immunoblot using recombinant intermediate filament subunits, suggests an indirect interaction of these proteins with the 12E8 antibody. In chick brain IPs, subunits of eukaryotic translation initiation factor 3 (EIF3) were found, but no direct interaction between 12E8 and recombinant Eif3e protein was detected. Fluorescence microscopy in primary cultured chick neurons showed evidence of co-localisation of Eif3e and tubulin labelling, consistent with previous data demonstrating cytoskeletal organisation of the translation apparatus. Neither total tau or MAP2 immunolabelling accumulated at ADF/cofilin-actin rods generated in primary cultured chick neurons, and we were unable to narrow down the major antigen recognised by 12E8 antibody on ADF/cofilin-actin rods.
Collapse
Affiliation(s)
- D. S. Davies
- Faculty of Medicine and Health, School of Medical Sciences, Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
| | - A. T. Arthur
- Faculty of Medicine and Health, School of Medical Sciences, Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
| | - H. L. Aitken
- Faculty of Medicine and Health, School of Medical Sciences, Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
| | - B. Crossett
- Sydney Mass Spectrometry, The University of Sydney, Sydney, NSW 2050, Australia
| | - C. S. Goldsbury
- Faculty of Medicine and Health, School of Medical Sciences, Brain and Mind Centre, The University of Sydney, Sydney, NSW 2050, Australia
| |
Collapse
|
2
|
Wu S, Hassan FU, Luo Y, Fatima I, Ahmed I, Ihsan A, Safdar W, Liu Q, Rehman SU. Comparative Genomic Characterization of Buffalo Fibronectin Type III Domain Proteins: Exploring the Novel Role of FNDC5/Irisin as a Ligand of Gonadal Receptors. BIOLOGY 2021; 10:1207. [PMID: 34827201 PMCID: PMC8615036 DOI: 10.3390/biology10111207] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2021] [Revised: 11/12/2021] [Accepted: 11/16/2021] [Indexed: 12/29/2022]
Abstract
FN-III proteins are widely distributed in mammals and are usually involved in cellular growth, differentiation, and adhesion. The FNDC5/irisin regulates energy metabolism and is present in different tissues (liver, brain, etc.). The present study aimed to investigate the physiochemical characteristics and the evolution of FN-III proteins and FNDC5/irisin as a ligand targeting the gonadal receptors including androgen (AR), DDB1 and CUL4 associated factor 6 (DCAF6), estrogen-related receptor β (ERR-β), estrogen-related receptor γ (ERR-γ), Krüppel-like factor 15 (KLF15), and nuclear receptor subfamily 3 group C member 1 (NR3C1). Moreover, the putative role of irisin in folliculogenesis and spermatogenesis was also elucidated. We presented the molecular structure and function of 29 FN-III genes widely distributed in the buffalo genome. Phylogenetic analysis, motif, and conserved domain pattern demonstrated the evolutionary well-conserved nature of FN-III proteins with a variety of stable to unstable, hydrophobic to hydrophilic, and thermostable to thermo-unstable properties. The comparative structural configuration of FNDC5 revealed amino acid variations but still the FNDC5 structure of humans, buffalo, and cattle was quite similar to each other. For the first time, we predicted the binding scores and interface residues of FNDC5/irisin as a ligand for six representative receptors having a functional role in energy homeostasis, and a significant involvement in folliculogenesis and spermatogenesis in buffalo.
Collapse
Affiliation(s)
- Siwen Wu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China; (S.W.); (Y.L.)
| | - Faiz-ul Hassan
- Institute of Animal and Dairy Sciences, University of Agriculture, Faisalabad 38040, Pakistan;
| | - Yuhong Luo
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China; (S.W.); (Y.L.)
| | - Israr Fatima
- Department of Bioinformatics and Biotechnology, Govt. College University, Faisalabad 38000, Pakistan;
| | - Ishtiaq Ahmed
- School of Medical Science, Gold Coast Campus, Griffith University, Southport, QLD 4222, Australia;
| | - Awais Ihsan
- Department of Biosciences, COMSATS University Islamabad, Sahiwal Campus, Sahiwal 57000, Pakistan;
| | - Warda Safdar
- Department of Biochemistry, Bahauddin Zakariya University, Multan 60000, Pakistan;
| | - Qingyou Liu
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China; (S.W.); (Y.L.)
| | - Saif ur Rehman
- State Key Laboratory for Conservation and Utilization of Subtropical Agro-Bioresources, Guangxi University, Nanning 530005, China; (S.W.); (Y.L.)
| |
Collapse
|
3
|
Bodakuntla S, Jijumon AS, Villablanca C, Gonzalez-Billault C, Janke C. Microtubule-Associated Proteins: Structuring the Cytoskeleton. Trends Cell Biol 2019; 29:804-819. [PMID: 31416684 DOI: 10.1016/j.tcb.2019.07.004] [Citation(s) in RCA: 165] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 11/27/2022]
Abstract
Microtubule-associated proteins (MAPs) were initially discovered as proteins that bind to and stabilize microtubules. Today, an ever-growing number of MAPs reveals a more complex picture of these proteins as organizers of the microtubule cytoskeleton that have a large variety of functions. MAPs enable microtubules to participate in a plethora of cellular processes such as the assembly of mitotic and meiotic spindles, neuronal development, and the formation of the ciliary axoneme. Although some subgroups of MAPs have been exhaustively characterized, a strikingly large number of MAPs remain barely characterized other than their interactions with microtubules. We provide a comprehensive view on the currently known MAPs in mammals. We discuss their molecular mechanisms and functions, as well as their physiological role and links to pathologies.
Collapse
Affiliation(s)
- Satish Bodakuntla
- Institut Curie, Paris Sciences et Lettres (PSL) Research University, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 3348, F-91405 Orsay, France; Université Paris Sud, Université Paris-Saclay, CNRS UMR 3348, F-91405 Orsay, France
| | - A S Jijumon
- Institut Curie, Paris Sciences et Lettres (PSL) Research University, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 3348, F-91405 Orsay, France; Université Paris Sud, Université Paris-Saclay, CNRS UMR 3348, F-91405 Orsay, France
| | - Cristopher Villablanca
- Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile; Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile
| | - Christian Gonzalez-Billault
- Center for Geroscience, Brain Health, and Metabolism (GERO), Santiago, Chile; Department of Biology, Faculty of Sciences, University of Chile, Santiago, Chile.
| | - Carsten Janke
- Institut Curie, Paris Sciences et Lettres (PSL) Research University, Centre National de la Recherche Scientifique (CNRS) Unité Mixte de Recherche (UMR) 3348, F-91405 Orsay, France; Université Paris Sud, Université Paris-Saclay, CNRS UMR 3348, F-91405 Orsay, France.
| |
Collapse
|
4
|
Tu HQ, Qin XH, Liu ZB, Song ZQ, Hu HB, Zhang YC, Chang Y, Wu M, Huang Y, Bai YF, Wang G, Han QY, Li AL, Zhou T, Liu F, Zhang XM, Li HY. Microtubule asters anchored by FSD1 control axoneme assembly and ciliogenesis. Nat Commun 2018; 9:5277. [PMID: 30538248 PMCID: PMC6290075 DOI: 10.1038/s41467-018-07664-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 11/07/2018] [Indexed: 01/07/2023] Open
Abstract
Defective ciliogenesis causes human developmental diseases termed ciliopathies. Microtubule (MT) asters originating from centrosomes in mitosis ensure the fidelity of cell division by positioning the spindle apparatus. However, the function of microtubule asters in interphase remains largely unknown. Here, we reveal an essential role of MT asters in transition zone (TZ) assembly during ciliogenesis. We demonstrate that the centrosome protein FSD1, whose biological function is largely unknown, anchors MT asters to interphase centrosomes by binding to microtubules. FSD1 knockdown causes defective ciliogenesis and affects embryonic development in vertebrates. We further show that disruption of MT aster anchorage by depleting FSD1 or other known anchoring proteins delocalizes the TZ assembly factor Cep290 from centriolar satellites, and causes TZ assembly defects. Thus, our study establishes FSD1 as a MT aster anchorage protein and reveals an important function of MT asters anchored by FSD1 in TZ assembly during ciliogenesis. Microtubule asters originate from centrosomes but their role during interphase remains largely unknown. Here, the authors find that microtubule asters anchored by previously-uncharacterized FSD1 play a role in ciliogenesis by maintaining the dynamic localization of centriolar satellites.
Collapse
Affiliation(s)
- Hai-Qing Tu
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Xuan-He Qin
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Zhi-Bin Liu
- University of Chinese Academy of Science, Beijing, 100101, China.,State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zeng-Qing Song
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Huai-Bin Hu
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Yu-Cheng Zhang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Yan Chang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Min Wu
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Yan Huang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Yun-Feng Bai
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Guang Wang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Qiu-Ying Han
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Ai-Ling Li
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Tao Zhou
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China
| | - Feng Liu
- State Key Laboratory of Biomembrane and Membrane Biotechnology, Institute of Zoology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Xue-Min Zhang
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China.
| | - Hui-Yan Li
- State Key Laboratory of Proteomics, National Center of Biomedical Analysis, Beijing, 100850, China. .,Cancer Research Institute of Jilin University, The First Hospital of Jilin University, Changchun, Jilin, 130021, China.
| |
Collapse
|
5
|
Florindo C, Perdigão J, Fesquet D, Schiebel E, Pines J, Tavares AA. Human Mob1 proteins are required for cytokinesis by controlling microtubule stability. J Cell Sci 2012; 125:3085-90. [PMID: 22454515 DOI: 10.1242/jcs.097147] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The completion of cytokinesis requires abscission of the midbody, a microtubule-rich cytoplasmic bridge that connects the daughter cells before their final separation. Although it has been established that both the midbody structure and membrane fusion are essential for abscission, the biochemical machinery and the cellular processes of abscission remain ill-defined. Here we report that human Mob1A and Mob1B proteins are involved in the regulation of abscission of the intercellular bridge. The Mob family is a group of highly conserved proteins in eukaryotes, described as binding partners as well as co-activators of protein kinases of the Ndr family, and as members of the Hippo pathway. We show that depletion of Mob1A and Mob1B by RNAi causes abscission failure as a consequence of hyper-stabilization of microtubules in the midbody region. Interestingly, depleting Mob1 also increases cell motility after cytokinesis, and induces prolonged centriole separation in G1 phase. In contrast, centrosomes fail to split when either Mob1A or Mob1B is overexpressed. Our findings indicate that human Mob1 proteins are involved in the regulation of microtubule stability at the midbody. We conclude that Mob1A and Mob1B are needed for cell abscission and centriole re-joining after telophase and cytokinesis.
Collapse
|
6
|
Hodgson L. New approaches to in-cell detection of protein activity: genetically encoded chemiluminescence probes pave the way to robust HTS assays. ACS Chem Biol 2008; 3:335-7. [PMID: 18570352 DOI: 10.1021/cb800136v] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
New genetically encoded biosensors utilizing the modified firefly luciferase promise a great improvement in the signal-to-noise ratio and the dynamic range of response in living cells. These biosensors are particularly suitable for high-throughput screening assays that use large-well-capacity formats because of their excellent response characteristics. The biosensor design strategies are highly generalizable and will be extremely valuable for expanding the repertoire of screenable targets in living cell systems.
Collapse
Affiliation(s)
- Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine of Yeshiva University, 1300 Morris Park Avenue, Price Center 217, Bronx, New York 10461
| |
Collapse
|
7
|
Tochio N, Koshiba S, Kobayashi N, Inoue M, Yabuki T, Aoki M, Seki E, Matsuda T, Tomo Y, Motoda Y, Kobayashi A, Tanaka A, Hayashizaki Y, Terada T, Shirouzu M, Kigawa T, Yokoyama S. Solution structure of the kinase-associated domain 1 of mouse microtubule-associated protein/microtubule affinity-regulating kinase 3. Protein Sci 2007; 15:2534-43. [PMID: 17075132 PMCID: PMC2242405 DOI: 10.1110/ps.062391106] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
Microtubule-associated protein/microtubule affinity-regulating kinases (MARKs)/PAR-1 are common regulators of cell polarity that are conserved from nematode to human. All of these kinases have a highly conserved C-terminal domain, which is termed the kinase-associated domain 1 (KA1), although its function is unknown. In this study, we determined the solution structure of the KA1 domain of mouse MARK3 by NMR spectroscopy. We found that approximately 50 additional residues preceding the previously defined KA1 domain are required for its proper folding. The newly defined KA1 domain adopts a compact alpha+beta structure with a betaalphabetabetabetabetaalpha topology. We also found a characteristic hydrophobic, concave surface surrounded by positively charged residues. This concave surface includes the highly conserved Glu-Leu-Lys-Leu motif at the C terminus, indicating that it is important for the function of the KA1 domain.
Collapse
Affiliation(s)
- Naoya Tochio
- RIKEN Genomic Sciences Center, Tsurumi, Yokohama 230-0045, Japan
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
8
|
Short KM, Cox TC. Subclassification of the RBCC/TRIM superfamily reveals a novel motif necessary for microtubule binding. J Biol Chem 2006; 281:8970-80. [PMID: 16434393 DOI: 10.1074/jbc.m512755200] [Citation(s) in RCA: 245] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The biological significance of RBCC (N-terminal RING finger/B-box/coiled coil) proteins is increasingly being appreciated following demonstrated roles in disease pathogenesis, tumorigenesis, and retroviral protective activity. Found in all multicellular eukaryotes, RBCC proteins are involved in a vast array of intracellular functions; but as a general rule, they appear to function as part of large protein complexes and possess ubiquitin-protein isopeptide ligase activity. Those members characterized to date have diverse C-terminal domain compositions and equally diverse subcellular localizations and functions. Using a bioinformatics approach, we have identified some new RBCC proteins that help define a subfamily that shares an identical domain arrangement (MID1, MID2, TRIM9, TNL, TRIM36, and TRIFIC). Significantly, we show that all analyzed members of this subfamily associate with the microtubule cytoskeleton, suggesting that subcellular compartmentalization is determined by the unique domain architecture, which may in turn reflect basic functional similarities. We also report a new motif called the COS box, which is found within these proteins, the MURF family, and a distantly related non-RBCC microtubule-binding protein. Notably, we demonstrate that mutations in the COS box abolish microtubule binding ability, whereas its incorporation into a nonmicrotubule-binding RBCC protein redirects it to microtubule structures. Further bioinformatics investigation permitted subclassification of the entire human RBCC complement into nine subfamilies based on their varied C-terminal domain compositions. This classification schema may aid the understanding of the molecular function of members of each subgroup and their potential involvement in both basic cellular processes and human disease.
Collapse
Affiliation(s)
- Kieran M Short
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, South Australia 5005, Australia
| | | |
Collapse
|
9
|
Mirouse V, Dastugue B, Couderc JL. The Drosophila Toucan protein is a new mitotic microtubule-associated protein required for spindle microtubule stability. Genes Cells 2005; 10:37-46. [PMID: 15670212 DOI: 10.1111/j.1365-2443.2004.00813.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mitotic spindle dynamics are highly dependent on proteins that interact with microtubules to influence their organization or stability. Here, we show that the Drosophila Toucan protein interacts directly with microtubules. Its localization to the microtubule network when it is expressed in mammalian cells and its direct interaction with microtubules in vitro are dependent on its central basic domain. Moreover, Toc expression in mammalian cells strongly protects microtubules from depolymerization. By using in vivo inducible RNAi in syncytial embryos, we generated a dose-sensitive loss of function of toucan, demonstrating that this technique is an efficient method for inactivating a maternal transcript. This enabled us to accurately characterize several new mitotic defects from the early to the late phases of mitosis, depending on Toucan depletion level. Toucan is required for metaphase spindle formation and centrosome anchoring to the poles. Then, during anaphase, Toc depletion affects kinetochore microtubules and therefore chromosome segregation. Toc is also necessary for central spindle formation by the interpolar microtubules. In contrast, astral microtubules are not disturbed by Toc depletion. Taken together, our results show that Toucan is a microtubule-associated protein specifically required for the stability of spindle microtubules throughout mitosis.
Collapse
Affiliation(s)
- Vincent Mirouse
- Institut National de la Santé et de la Recherche Médicale UMR384, Laboratoire de Biochimie, UFR Médecine, 28, place Henri Dunant, 63001 Clermont-Fd, France
| | | | | |
Collapse
|
10
|
Webb DJ, Brown CM, Horwitz AF. Illuminating adhesion complexes in migrating cells: moving toward a bright future. Curr Opin Cell Biol 2004; 15:614-20. [PMID: 14519397 DOI: 10.1016/s0955-0674(03)00105-4] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Cell migration is a complex, tightly regulated process that involves the continuous formation and disassembly of adhesions. Despite the importance of these processes, very little is known about the factors that regulate adhesion dynamics during migration. Recent advances in imaging technologies are allowing monitoring of these processes during migration and are providing insight into the mechanisms that regulate them.
Collapse
Affiliation(s)
- Donna J Webb
- Department of Cell Biology, University of Virginia Health Sciences Center, Charlottesville, VA 22908, USA.
| | | | | |
Collapse
|
11
|
Berti C, Fontanella B, Ferrentino R, Meroni G. Mig12, a novel Opitz syndrome gene product partner, is expressed in the embryonic ventral midline and co-operates with Mid1 to bundle and stabilize microtubules. BMC Cell Biol 2004; 5:9. [PMID: 15070402 PMCID: PMC385223 DOI: 10.1186/1471-2121-5-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2003] [Accepted: 02/29/2004] [Indexed: 12/05/2022] Open
Abstract
BACKGROUND Opitz G/BBB syndrome is a genetic disorder characterized by developmental midline abnormalities, such as hypertelorism, cleft palate, and hypospadias. The gene responsible for the X-linked form of this disease, MID1, encodes a TRIM/RBCC protein that is anchored to the microtubules. The association of Mid1 with the cytoskeleton is regulated by dynamic phosphorylation, through the interaction with the alpha4 subunit of phosphatase 2A (PP2A). Mid1 acts as an E3 ubiquitin ligase, regulating PP2A degradation on microtubules. RESULTS In spite of these findings, the biological role exerted by the Opitz syndrome gene product is still unclear and the presence of other potential interacting moieties in the Mid1 structure prompted us to search for additional cellular partners. Through a yeast two-hybrid screening approach, we identified a novel gene, MIG12, whose protein product interacts with Mid1. We confirmed by immunoprecipitation that this interaction occurs in vivo and that it is mediated by the Mid1 coiled-coil domain. We found that Mig12 is mainly expressed in the neuroepithelial midline, urogenital apparatus, and digits during embryonic development. Transiently expressed Mig12 is found diffusely in both nucleus and cytoplasm, although it is enriched in the microtubule-organizing center region. Consistently with this, endogenous Mig12 protein is partially detected in the polymerized tubulin fraction after microtubule stabilization. When co-transfected with Mid1, Mig12 is massively recruited to thick filamentous structures composed of tubulin. These microtubule bundles are resistant to high doses of depolymerizing agents and are composed of acetylated tubulin, thus representing stabilized microtubule arrays. CONCLUSIONS Our findings suggest that Mig12 co-operates with Mid1 to stabilize microtubules. Mid1-Mig12 complexes might be implicated in cellular processes that require microtubule stabilization, such as cell division and migration. Impairment in Mig12/Mid1-mediated microtubule dynamic regulation, during the development of embryonic midline, may cause the pathological signs observed in Opitz syndrome patients.
Collapse
Affiliation(s)
- Caterina Berti
- Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
- Present address: DIBIT – HSR Hospital, Milan, Italy
| | - Bianca Fontanella
- Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | - Rosa Ferrentino
- Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| | - Germana Meroni
- Telethon Institute of Genetics and Medicine (TIGEM), 80131 Naples, Italy
| |
Collapse
|
12
|
Gromley A, Jurczyk A, Sillibourne J, Halilovic E, Mogensen M, Groisman I, Blomberg M, Doxsey S. A novel human protein of the maternal centriole is required for the final stages of cytokinesis and entry into S phase. J Cell Biol 2003; 161:535-45. [PMID: 12732615 PMCID: PMC2172935 DOI: 10.1083/jcb.200301105] [Citation(s) in RCA: 205] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Centrosomes nucleate microtubules and contribute to mitotic spindle organization and function. They also participate in cytokinesis and cell cycle progression in ways that are poorly understood. Here we describe a novel human protein called centriolin that localizes to the maternal centriole and functions in both cytokinesis and cell cycle progression. Centriolin silencing induces cytokinesis failure by a novel mechanism whereby cells remain interconnected by long intercellular bridges. Most cells continue to cycle, reenter mitosis, and form multicellular syncytia. Some ultimately divide or undergo apoptosis specifically during the protracted period of cytokinesis. At later times, viable cells arrest in G1/G0. The cytokinesis activity is localized to a centriolin domain that shares homology with Nud1p and Cdc11p, budding and fission yeast proteins that anchor regulatory pathways involved in progression through the late stages of mitosis. The Nud1p-like domain of centriolin binds Bub2p, another component of the budding yeast pathway. We conclude that centriolin is required for a late stage of vertebrate cytokinesis, perhaps the final cell cleavage event, and plays a role in progression into S phase.
Collapse
Affiliation(s)
- Adam Gromley
- University of Massachusetts Medical School, Department of Molecular Medicine, Worcester, MA 01605, USA
| | | | | | | | | | | | | | | |
Collapse
|