Pharmaceutical Sciences Faculty Publications

Title

Direct Phosphorylation and Activation of a Nim1-Related Kinase Gin4 by Elm1 in Budding Yeast

Document Type

Article

Publication Date

9-15-2006

Journal Title

The Journal of Biological Chemistry

ISSN

0021-9258

Volume

281

Issue

37

First Page

27090

Last Page

27098

DOI

10.1074/jbc.M601483200

PubMed ID

16861226

Abstract

In budding yeast, Gin4, a Nim1-related kinase, plays an important role in proper organization of the septin ring at the mother-bud neck, a filamentous structure that is critical for diverse cellular processes including mitotic entry and cytokinesis. How Gin4 kinase activity is regulated is not known. Here we showed that a neck-associated Ser/Thr kinase Elm1, which is important for septin assembly, is critical for proper modification of Gin4 and its physiological substrate Shs1. In vitro studies with purified recombinant proteins demonstrated that Elm1 directly phosphorylates and activates Gin4, which in turn phosphorylates Shs1. Consistent with these observations, acute inhibition of Elm1 activity abolished mitotic Gin4 phosphorylation and Gin4-dependent Shs1 modification in vivo. In addition, a gin4 mutant lacking the Elm1-dependent phosphorylation sites exhibited an impaired localization to the bud-neck and, as a result, induced a significant growth defect with an elongated bud morphology. Thus, Elm1 regulates the septin assembly-dependent cellular events by directly phosphorylating and activating the Gin4-dependent pathway(s).

Keywords

Animals, cyclin-dependent kinases, enzyme activation, gene expression regulation, enzymologic, gene expression regulation, fungal, insecta, membrane proteins, models, biological, peptides, phosphorylation, plasmids, protein kinases

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