protein regulator of cytokinesis 1 (PRC1)

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Function

key regulator of cytokinesis
cross-links antiparrallel microtubules at an average distance of 35 nM
essential for controlling the spatiotemporal formation of the midzone & successful cytokinesis
required for KIF14 localization to the central spindle & midbody
required to recruit PLK1 to the spindle
stimulates PLK1 phosphorylation of RACGAP1 to allow recruitment of ECT2 to the central spindle
phosphorylation by CDK1 in early mitosis holds PRC1 in an inactive monomeric state
- phosphorylation by CDK1 prevents PLK1-binding
- CDK1 is degraded at anaphase & dephosphorylation
during the metaphase to anaphase transition, PRC1 is dephosphorylated, promoting interaction with KIF4A, which then translocates PRC1 along mitotic spindles to the plus ends of antiparallel interdigitating microtubules
dephosphorylation also promotes microtubule-bundling activity by allowing dimerization.
KIF4A translocates PRC1 to the plus ends of interdigitating spindle microtubules during the metaphase to anaphase transition
- microtubule-binding & bundling protein both in vivo & in vitro
interacts with the C-terminal Rho-GAP domain & the basic region of RACGAP1
interaction with RACGAP1 inhibits its GAP activity towards CDC42
interacts separately via its N-terminal region with the C-terminus of CENPE, KIF4A, KIF23 during late mitosis
phosphorylation: very weak in G1/S phase cells, reaches a maximum during mitosis

homodimer
microtubule binding occurs via a basic patch in the central spectrin-like domain & requires also the C-terminal domain
belongs to the MAP65/ASE1 family,