Microtubule plus-ends act as physical signaling hubs to activate RhoA during cytokinesis

In this study cytokinesis regulators visualized inDrosophila melanogaster (Dm) cells were found to localize to and track MT plus-ends during cytokinesis. The RhoA GEF Pebble (DmECT2) did not evidently tip-track, but rather localized rapidly to cortical sites contacted by MT plus-tips, resulting in RhoA activation and enrichment of myosin-regulatory light chain. The MT plus-end localization of centralspindlin was compromised following EB1 depletion, which resulted in a higher incidence of cytokinesis failure. Centralspindlin plus-tip localization depended on the C-terminus and a putative EB1-interaction motif (hxxPTxh) in RacGAP50C. We propose that MT plus-end-associated centralspindlin recruits a cortical pool ofDmECT2 upon physical contact to activate RhoA and to trigger localized contractility.
Source: eLife - Category: Biomedical Science Tags: Cell Biology Source Type: research