Calcium-dependent activation of Pyk2 by hypoxia.
The Pyk2 tyrosine kinase can be activated by both calcium-dependent and calcium-independent mechanisms. Exposure to moderate hypoxia (5% O(2)) induced a rapid and persistent tyrosine phosphorylation of Pyk2 in pheochromocytoma (PC12) cells. Hypoxia and KCl-depolarization increased the phosphotyrosine content of Pyk2 by twofold and fourfold, respectively. Both of these effects were abolished in the absence of extracellular calcium. There was a modest activation of MAPK in parallel with the onset of Pyk2 phosphorylation. However, there was no detectable activation of either JNK or c-src, two other known downstream targets of Pyk2. Thus, exposure to hypoxia may selectively target specific subsets of Pyk2 signalling pathways.
Beitner-Johnson
Dana
D
Department of Molecular and Cellular Physiology, College of Medicine, University of Cincinnati, P.O. Box 67-0576, Cincinnati, OH 45267-0576, USA.
Ferguson
Tsuneo
T
Rust
Randy T
RT
Kobayashi
Shuichi
S
Millhorn
David E
DE
D000818:Animals; D015153:Blotting, Western; D002118:Calcium / Q000494:pharmacology*; D020013:Calcium Signaling; D015687:Cell Hypoxia; D004789:Enzyme Activation; D051418:Focal Adhesion Kinase 2; D007700:Kinetics; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016716:PC12 Cells; D010766:Phosphorylation; D011189:Potassium Chloride / Q000494:pharmacology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D051381:Rats
D011189:Potassium Chloride; D011505:Protein-Tyrosine Kinases; D051418:Focal Adhesion Kinase 2; C496054:Ptk2b protein, rat; D020928:Mitogen-Activated Protein Kinases; D002118:Calcium