Phosphoinositide 3-kinase C2alpha Links Clathrin to Microtubule-dependent Movement.
From: Department of Biochemistry and Molecular Biology, Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA.
The Journal of biological chemistry
- Publish Date: Jan 2007
- ISSN: 0021-9258
- Volume: 282
- Issue: 2
- Pages: 1249-56
- Medium: Print
- Language: English
- Citation (JAMA): Zhao Yanqiu, Gaidarov Ibragim, Keen James H, et al. Phosphoinositide 3-kinase C2alpha Links Clathrin to Microtubule-dependent Movement.. J. Biol. Chem. Jan 2007;282:1249-56
Abstract
Phosphoinositide 3-kinase C2alpha (PI3K-C2alpha) is a type II PI-3-kinase that has been implicated in several important membrane transport and signaling processes. We previously found that overexpression of PI3K-C2alpha inhibits clathrin-mediated membrane trafficking and induces proliferation of novel clathrin-coated structures within the cytoplasm. Using fluorescently tagged fusions of PI3K-C2alpha and clathrin, we explored the behavior of these structures in intact cells. Both proteins are present in the structures, and using rapid image acquisition and fluorescence photoactivation probes, we find that they exhibit localized, rapid mobility (5-20 microm/s). The movement is micro-tubule-based as revealed by use of inhibitors, and PI3K-C2alpha accumulates on microtubules rapidly and reversibly following cytoplasmic acidification, which also blocks movement. Dynactin mediates the movement of these clathrin-PI3K-C2alpha structures, since disruption of dynactin function by overexpression of its p50 subunit also inhibits movement. Finally, immunoprecipitation experiments reveal an interaction between endogenous PI3K-C2alpha and dynactin subunits. Together, these results reveal a molecular linkage between PI3K-C2alpha and the microtubule motor machinery, with implications for membrane trafficking in intact cells.
Mesh Headings (Keywords): 1-Phosphatidylinositol 3-Kinase, Animals, Antibodies, Biological Transport, Cells, Cultured, Clathrin, Cytoplasm, Humans, Microtubule-Associated Proteins, Microtubules, Molecular Motor Proteins, Protein Transport, Rabbits, Recombinant Fusion Proteins
Check for Full Text / PubMed Unique Identifier (PMID): 17110375
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