Imp2p forms actin-dependent clusters and imparts stiffness to the contractile ring

Area of Science:

• Cell biology
• Molecular and cell biology
• Biochemistry

Background:

• The contractile ring is essential for cell division, requiring stable anchoring to the plasma membrane and cell wall to transmit tension.
• F-BAR domain proteins like Imp2p and Cdc15p in fission yeast are implicated as key anchoring proteins due to observed mutant phenotypes.

Purpose of the Study:

• To investigate the role of Imp2p in contractile ring function and its relationship with Cdc15p during fission yeast cytokinesis.
• To elucidate the molecular mechanisms underlying the contribution of Imp2p and Cdc15p to contractile ring stability and assembly.

Main Methods:

• Analysis of Imp2p protein clustering and dependence on the actin network.
• Investigating the reciprocal influence of Imp2p and Cdc15p on their respective protein levels within the contractile ring.

Main Results:

• Imp2p, similar to Cdc15p, contributes to contractile ring stiffness and forms stable protein clusters dependent on the actin network.
• Imp2p clusters consist of approximately eight Imp2p dimers and are stabilized at the division plane by the actin network.
• Imp2p and Cdc15p exhibit reciprocal regulation, affecting each other's abundance in the contractile ring.

Conclusions:

• Imp2p plays a significant role in maintaining contractile ring stiffness and stability during cytokinesis.
• The interdependent relationship between Imp2p and Cdc15p is crucial for proper contractile ring function and may explain their shared phenotypic characteristics.