Proteomic screen defines the Polo-box domain interactome and identifies Rock2 as a Plk1 substrate.

EMBO J
Authors
Keywords
Abstract

Polo-like kinase-1 (Plk1) phosphorylates a number of mitotic substrates, but the diversity of Plk1-dependent processes suggests the existence of additional targets. Plk1 contains a specialized phosphoserine-threonine binding domain, the Polo-box domain (PBD), postulated to target the kinase to its substrates. Using the specialized PBD of Plk1 as an affinity capture agent, we performed a screen to define the mitotic Plk1-PBD interactome by mass spectrometry. We identified 622 proteins that showed phosphorylation-dependent mitosis-specific interactions, including proteins involved in well-established Plk1-regulated processes, and in processes not previously linked to Plk1 such as translational control, RNA processing, and vesicle transport. Many proteins identified in our screen play important roles in cytokinesis, where, in mammalian cells, the detailed mechanistic role of Plk1 remains poorly defined. We go on to characterize the mitosis-specific interaction of the Plk1-PBD with the cytokinesis effector kinase Rho-associated coiled-coil domain-containing protein kinase 2 (Rock2), demonstrate that Rock2 is a Plk1 substrate, and show that Rock2 colocalizes with Plk1 during cytokinesis. Finally, we show that Plk1 and RhoA function together to maximally enhance Rock2 kinase activity in vitro and within cells, and implicate Plk1 as a central regulator of multiple pathways that synergistically converge to regulate actomyosin ring contraction during cleavage furrow ingression.

Year of Publication
2007
Journal
EMBO J
Volume
26
Issue
9
Pages
2262-73
Date Published
2007 May 02
ISSN
0261-4189
URL
DOI
10.1038/sj.emboj.7601683
PubMed ID
17446864
PubMed Central ID
PMC1864981
Links
Grant list
R01 GM060594 / GM / NIGMS NIH HHS / United States
U54 CA112962 / CA / NCI NIH HHS / United States
GM60594 / GM / NIGMS NIH HHS / United States
P50-CA112962 / CA / NCI NIH HHS / United States