Identification of p21-Activated Kinase Specificity Determinants in Budding Yeast: a Single Amino Acid Substitution Imparts Ste20 Specificity to Cla4

AUTOR(ES)

Keniry, Megan E.

FONTE

American Society for Microbiology

RESUMO

Two closely related p21-activated kinases from Saccharomyces cerevisiae, Ste20 and Cla4, interact with and are regulated by Cdc42, a small Rho-like GTPase. These kinases are argued to perform a common essential function, based on the observation that the single mutants are viable whereas the double mutant is inviable. Despite having a common upstream regulator and at least one common function, these molecules also have many distinct cellular signaling roles. Ste20 signals upstream of several mitogen-activated protein kinase cascades (e.g., pheromone response, filamentous growth, and high osmolarity), and Cla4 signals during budding and cytokinesis. In order to investigate how these kinases are directed to distinct functions, we sought to identify specificity determinants within Ste20 and Cla4. To this end, we constructed both chimeric fusions and point mutants and tested their ability to perform unique and shared cellular roles. Specificity determinants for both kinases were mapped to the C-terminal kinase domains. Remarkably, the substitution of a single amino acid, threonine 818, from Ste20 into an otherwise wild-type Cla4, Cla4D772T, conferred the ability to perform many Ste20-specific functions.

Documentos Relacionados

• Cdc42 Regulation of Kinase Activity and Signaling by the Yeast p21-Activated Kinase Ste20
• Synthetic Lethal Analysis Implicates Ste20p, a p21-activated Protein Kinase, in Polarisome ActivationD⃞
• p21-activated kinase has substrate specificity similar to Acanthamoeba myosin I heavy chain kinase and activates Acanthamoeba myosin I
• Regulation of Macropinocytosis by p21-activated Kinase-1
• GIT1 Activates p21-Activated Kinase through a Mechanism Independent of p21 Binding