Verprolin cytokinesis function mediated by the Hof one trap domain.
In budding yeast, partitioning of the cytoplasm during cytokinesis can proceed via a pathway dependent on the contractile actomyosin ring, as in other eukaryotes, or alternatively via a septum deposition pathway dependent on an SH3 domain protein, Hof1/Cyk2 (the yeast PSTPIP1 ortholog). In dividing yeast cells, Hof1 forms a ring at the bud neck distinct from the actomyosin ring, and this zone is active in septum deposition. We previously showed the yeast Wiskott-Aldrich syndrome protein (WASP)-interacting protein (WIP) ortholog, verprolin/Vrp1/End5, interacts with Hof1 and facilitates Hof1 recruitment to the bud neck. A Vrp1 fragment unable to interact with yeast WASP (Las17/Bee1), localize to the actin cytoskeleton or function in polarization of the cortical actin cytoskeleton nevertheless retains function in Hof1 recruitment and cytokinesis. Here, we show the ability of this Vrp1 fragment to bind the Hof1 SH3 domain via its Hof one trap (HOT) domain is critical for cytokinesis. The Vrp1 HOT domain consists of three tandem proline-rich motifs flanked by serines. Unexpectedly, the Hof1 SH3 domain itself is not required for cytokinesis and indeed appears to negatively regulate cytokinesis. The Vrp1 HOT domain promotes cytokinesis by binding to the Hof1 SH3 domain and counteracting its inhibitory effect.
Ren
Gang
G
Laboratory of Yeast Cell Biology, Institute of Molecular and Cell Biology, A*STAR Biomedical Sciences Institutes, Singapore, 138673, Republic of Singapore.
Wang
Juan
J
Brinkworth
Ross
R
Winsor
Barbara
B
Kobe
Bostjan
B
Munn
Alan L
AL
D020816:Amino Acid Motifs; D002453:Cell Cycle / Q000502:physiology*; D008840:Microfilament Proteins / Q000378:metabolism / Q000502:physiology*; D008869:Microtubule-Associated Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D008958:Models, Molecular; D012441:Saccharomyces cerevisiae / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D012694:Serine / Q000378:metabolism; D018909:src Homology Domains
C116847:HOF1 protein, S cerevisiae; D008840:Microfilament Proteins; D008869:Microtubule-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins; C090350:VRP1 protein, S cerevisiae; D012694:Serine