The Role of Phosphatidic Acid in PIPKI-regulated Actin Reorganization
Journal Title
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Issue Date
1-Aug-10
Authors
Roach, Akua Ntiamoah
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Keywords
Abstract
Production and breakdown of certain phosphoinositides plays key roles in a variety of cellular processes. Among these, phosphatidylinositol-4, 5-phosphate (PIP <sub>2</sub>) is well known for its critical functions in membrane trafficking, cytoskeletal organization, and signal transduction. Type I phosphatidylinositol-4-phosphate 5-kinase (PIPKI) is the main enzyme responsible for the synthesis of PIP<sub>2</sub>. Although PIPKI activity is regulated by small G proteins and phosphatidic acid (PA), the contribution of these upstream regulators in actin cytoskeletal reorganization remains unclear. The binding region of some other PA-regulated proteins has been identified. From these, it appears that binding may either be direct or electrostatic in nature. I have identified basic residues in the proposed membrane-binding region of PIPKIΓ that are required for membrane translocation, actin reorganization, and stimulation by PA. I also demonstrate here that the direct binding of PIPKI to PA through these residues is required for these important functions.