PRC1 is a microtubule binding and bundling protein essential to maintain the mitotic spindle midzone []. It is a key regulator of cytokinesis that cross-links antiparallel microtubules at an average distance of 35 nM [, ]. PRC1 is also required for KIF14 (a kinesin-3 family motor protein) localisation to the central spindle and midbody [, , ]and is required to recruit PLK1 to the spindle. It stimulates PLK1 phosphorylation of RACGAP1/HsCyk-4 to allow recruitment of ECT2 to the central spindle [].
This is a family of microtubule associated proteins, including MAP65 (MAP65-1/2/3/4/5/6/7/8/9) from Arabidopsis, Ase1 from yeast, and PRC1 from mammals.Ase1 is required for spindle elongation and stabilisation. It is cell cycle-regulated by anaphase promoting complex []. It is a potential Cdc28p substrate []. MAP65-1 plays a role in stabilising anti-parallel microtubules in the central spindle at anaphase to early cytokinesis. MAP65-1 is cell cycle regulated by phosphorylation [, , , , ].PRC1 is a microtubule binding and bundling protein essential to maintain the mitotic spindle midzone []. It is a key regulator of cytokinesis that cross-links antiparallel microtubules at an average distance of 35 nM [, ]. PRC1 is also required for KIF14 (a kinesin-3 family motor protein) localisation to the central spindle and midbody [, , ]and is required to recruit PLK1 to the spindle. It stimulates PLK1 phosphorylation of RACGAP1/HsCyk-4 to allow recruitment of ECT2 to the central spindle [].
Citron Rho-interacting kinase (CRIK) is a dual specificity protein kinase, which catalyses the autophosphorylation and phosphorylation of exogenous substrates on both serine/threonine and tyrosine residues []. It plays an important role in the regulation of cytokinesis and the development of the central nervous system. It is required for KIF14 localization to the central spindle and mid-body. It is also a putative RHO/RAC effector that binds to the GTP-bound forms of RHO and RAC1. This protein occurs in at least two different isoforms: CRIK (about 240kDa), in which the kinase domain is followed by the sequence of Citron (a Rho/Rac binding protein); and CRIK-short kinase (CRIK-SK, about 54kDa), which consists mostly of the kinase domain. CRIK may fulfil more specialised functions in specific cell types [].
