Anillin forms linear structures and facilitates furrow ingression after septin and formin depletion

• Published in: Cell reports (Cambridge) 2023-09, Vol.42 (9), p.113076-113076, Article 113076
• Main Authors: Lebedev, Mikhail, Chan, Fung-Yi, Lochner, Anna, Bellessem, Jennifer, Osório, Daniel S., Rackles, Elisabeth, Mikeladze-Dvali, Tamara, Carvalho, Ana Xavier, Zanin, Esther
• Format: Article
• Language: English
• Subjects: actin; Actins - metabolism; anillin; Animals; C. elegans; Caenorhabditis elegans - metabolism; Caenorhabditis elegans Proteins - genetics; Caenorhabditis elegans Proteins - metabolism; cell division; Cell Membrane - metabolism; Contractile Proteins; contractile ring; CP: Cell biology; cytokinesis; Cytokinesis - physiology; formin; Formins - metabolism; intrinsically disordered; liquid-liquid phase separation; Microfilament Proteins - genetics; Microfilament Proteins - metabolism; myosin; Myosin Type II - metabolism; Septins - genetics; Septins - metabolism
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2023.113076

During cytokinesis, a contractile ring consisting of unbranched filamentous actin (F-actin) and myosin II constricts at the cell equator. Unbranched F-actin is generated by formin, and without formin no cleavage furrow forms. In Caenorhabditis elegans, depletion of septin restores furrow ingression in formin mutants. How the cleavage furrow ingresses without a detectable unbranched F-actin ring is unknown. We report that, in this setting, anillin (ANI-1) forms a meshwork of circumferentially aligned linear structures decorated by non-muscle myosin II (NMY-2). Analysis of ANI-1 deletion mutants reveals that its disordered N-terminal half is required for linear structure formation and sufficient for furrow ingression. NMY-2 promotes the circumferential alignment of the linear ANI-1 structures and interacts with various lipids, suggesting that NMY-2 links the ANI-1 network with the plasma membrane. Collectively, our data reveal a compensatory mechanism, mediated by ANI-1 linear structures and membrane-bound NMY-2, that promotes furrowing when unbranched F-actin polymerization is compromised. [Display omitted] •An anillin-dependent compensatory mechanism drives furrowing if F-actin is low•The disordered anillin N terminus forms linear structures under the plasma membrane•Non-muscle myosin II represents in independent membrane anchor during cytokinesis•The anillin ring constricts to form a cleavage furrow when septins are also reduced During cytokinesis in animal cells, an actin-based ring constricts at the cell equator to form the cleavage furrow. Lebedev et al. discover a compensatory mechanism mediated by linear anillin structures and membrane-bound myosin II that drives cleavage furrow formation and ingression in case actin ring assembly fails.