| Primary Identifier | IPR037791 | Type | Domain |
| Short Name | C2_fungal_Inn1 |
| description | Saccharomyces cerevisiae Inn1 associates with the contractile actomyosin ring at the end of mitosis and is needed for cytokinesis []. The C2 domain of Inn1, located at the N terminus, is required for ingression of the plasma membrane. The C terminus is relatively unstructured and contains eight PXXP motifs that are thought to mediate interaction of Inn1 with SH3 domains in the cytokinesis proteins Hof1 (an F-BAR protein) and Cyk3 (whose overexpression can restore primary septum formation in Inn1Delta cells) as well as recruiting Inn1 to the bud-neck by binding to Cyk3 [, ]. Inn1 and Cyk3 appear to cooperate in activating chitin synthase Chs2 for primary septum formation, which allows coordination of actomyosin ring contraction with ingression of the cleavage furrow []. It is thought that the C2 domain of Inn1 helps to preserve the link between the actomyosin ring and the plasma membrane, contributing both to membrane ingression, as well as to stability of the contracting ring. Additionally, Inn1 might induce curvature of the plasma membrane adjacent to the contracting ring, thereby promoting ingression of the membrane []. S. pombe Inn1 is also involved in the ingression of the plasma membrane during cytokinesis. However, it does not play an essential role, probably because the actinomyosin ring is connected to the cell cortex by many more proteins []. |
