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

Area of Science:

• Cell biology
• Molecular and developmental biology

Background:

• Cytokinesis requires a contractile ring of actin and myosin II for cell division.
• Formin proteins generate unbranched actin filaments essential for cleavage furrow formation.
• Septin depletion can rescue furrow ingression in formin mutants, but the mechanism is unclear.

Purpose of the Study:

• To investigate the mechanism of cleavage furrow ingression in the absence of a detectable unbranched actin ring.
• To elucidate the role of anillin (ANI-1) and non-muscle myosin II (NMY-2) in compensatory cytokinesis.

Main Methods:

• Analysis of anillin (ANI-1) deletion mutants in Caenorhabditis elegans.
• Microscopic observation of cellular structures during cytokinesis.
• Investigating the interaction between anillin and myosin II.

Main Results:

• Anillin (ANI-1) forms a meshwork of circumferentially aligned linear structures in formin mutants.
• The disordered N-terminal half of ANI-1 is crucial for linear structure formation and furrowing.
• Non-muscle myosin II (NMY-2) aligns ANI-1 structures and interacts with lipids, linking the network to the plasma membrane.

Conclusions:

• Anillin-mediated linear structures and membrane-associated NMY-2 provide a compensatory mechanism for cytokinesis when actin polymerization is compromised.
• This pathway highlights an alternative strategy for cell division independent of the canonical actin contractile ring.