Cyclic modulation of cytoskeleton assembly-disassembly by the ATP.Mg-dependent protein phosphatase activator (kinase FA).
The ATP.Mg-dependent protein phosphatase activating factor (FA) has been identified as a microtubule protein kinase and as a microtubule protein phosphatase activator. FA could phosphorylate microtubule-associated tau protein up to 4 moles of phosphates per mole of protein. However, more than 80% of the phosphates in 32P-tau phosphorylated by FA could be removed by ATP.Mg-dependent protein phosphatase and the tau phosphatase activity was FA-dependent. Functional study further revealed that as a tau kinase, FA could phosphorylate tau and thereby inhibits cross-linking copolymerization of tau with tubulin and actin filaments whereas as a tau phosphatase activating factor, FA could promote copolymerization of tau with tubulin and actin filaments. Taken together, the results provide evidence that a cyclic modulation of cytoskeleton assembly-disassembly can be controlled by FA, representing an efficient cyclic cascade mechanism for rapid structural and functional regulation of cytoskeletal system in the central nervous system.
Institute of Biomedical Science, National Tsing Hua University, Hsinchu, Taiwan, ROC.
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D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000378:metabolism; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D003598:Cytoskeletal Proteins / Q000302:isolation & purification / Q000378:metabolism*; D003599:Cytoskeleton / Q000378:metabolism* / Q000648:ultrastructure; D004591:Electrophoresis, Polyacrylamide Gel; D007700:Kinetics; D010749:Phosphoprotein Phosphatases / Q000302:isolation & purification / Q000378:metabolism*; D011494:Protein Kinases / Q000378:metabolism*; D016875:tau Proteins / Q000302:isolation & purification / Q000378:metabolism
D003598:Cytoskeletal Proteins; D016875:tau Proteins; D000255:Adenosine Triphosphate; D011494:Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D010749:Phosphoprotein Phosphatases