Control of Fission Yeast Cell Morphogenesis by the Conserved Protein Kinase Orb6p

University Of Miami School Of Medicine, Coral Gables FL

Investigators

Abstract

Eukaryotic cells establish and maintain polarized cellular domains which are essential for intracellular transport, cell differentiation, cell shape and cell locomotion. Previous studies identified nineteen independent genes that control cell morphogenesis in fission yeast. One of these genes, orb6, has a key role in the regulation of both cell shape and cell proliferation. Orb6p is ser/thr protein kinase that is conserved in higher eukaryotes, and is related to mammalian LATS kinase. The objective of this project is to define the Orb6p kinase effectors that regulate cell morphology and to determine the mechanisms of control of Orb6p kinase. Studies will be performed that address the following aspects of Orb6p function: (1) Spatial and temporal control of cell morphology by Orb6p kinase. Using a combined biochemical, cell imaging and genetic approach this project will establish: (a) the role of Orb6p kinase activity in the control of polarized cell growth and the cytoskeleton; (b) The presence of cytoskeleton control proteins in the multiprotein complex associated with Orb6p kinase; (c) The role of Orb6p-associated proteins as substrate targets of the Orb6p kinase in the control of cell morphology. (2) Mechanisms of control of Orb6p kinase activity. Previous studies have found that Orb6p is phosphorylated in vivo and that Orb6p kinase activity is strongly stimulated by hyper-osmotic stress. These studies intend to: (a) examine changes in Orb6p protein phosphorylation in response to hyper-osmotic stress; (b) test specific kinase pathways for their involvement in the control of Orb6p protein phosphorylation and Orb6p kinase activity. These studies will offer training opportunities in biochemical, yeast genetics and microscopical techniques to researchers of different backgrounds and levels of education, including high school, undergraduate and graduate students, and medical fellows.