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Silva AM, Chan FY, Norman MJ, Sobral AF, Zanin E, Gassmann R, Belmonte JM, Carvalho AX. β-heavy-spectrin stabilizes the constricting contractile ring during cytokinesis. J Cell Biol 2022; 222:213538. [PMID: 36219157 PMCID: PMC9559602 DOI: 10.1083/jcb.202202024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Revised: 08/17/2022] [Accepted: 09/20/2022] [Indexed: 11/22/2022] Open
Abstract
Cytokinesis requires the constriction of an actomyosin-based contractile ring and involves multiple F-actin crosslinkers. We show that partial depletion of the C. elegans cytokinetic formin generates contractile rings with low F-actin levels that constrict but are structurally fragile, and we use this background to investigate the roles of the crosslinkers plastin/PLST-1 and β-heavy-spectrin/SMA-1 during ring constriction. We show that the removal of PLST-1 or SMA-1 has opposite effects on the structural integrity of fragile rings. PLST-1 loss reduces cortical tension that resists ring constriction and makes fragile rings less prone to ruptures and regressions, whereas SMA-1 loss exacerbates structural defects, leading to frequent ruptures and cytokinesis failure. Fragile rings without SMA-1 or containing a shorter SMA-1, repeatedly rupture at the same site, and SMA-1::GFP accumulates at repair sites in fragile rings and in rings cut by laser microsurgery. These results establish that β-heavy-spectrin stabilizes the constricting ring and reveals the importance of β-heavy-spectrin size for network connectivity at low F-actin density.
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Affiliation(s)
- Ana Marta Silva
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Fung-Yi Chan
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Michael J. Norman
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Filipa Sobral
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Esther Zanin
- Department Biologie, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany
| | - Reto Gassmann
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal
| | - Julio Monti Belmonte
- Department of Physics, North Carolina State University, Raleigh, NC,Quantitative and Computational Developmental Biology Cluster, North Carolina State University, Raleigh, NC
| | - Ana Xavier Carvalho
- i3S—Instituto de Investigação e Inovação em Saúde, Universidade do Porto, Porto, Portugal,IBMC—Instituto de Biologia Molecular e Celular, Universidade do Porto, Porto, Portugal,Correspondence to Ana Xavier Carvalho:
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