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Activation of protein phosphatase 5 by limited proteolysis or the binding of polyunsaturated fatty acids to the TPR domain
Author(s) -
Chen Mao Xiang,
Cohen Patricia T.W
Publication year - 1997
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(96)01427-5
Subject(s) - biochemistry , proteolysis , polyunsaturated fatty acid , chemistry , phosphatase , allosteric regulation , phosphatidylinositol , enzyme , fatty acid , signal transduction
Protein phosphatase 5 (PP5) exhibits very low phosphatase activity, which can be stimulated >25‐fold by proteolysis. Since proteolysis cleaves the N‐terminal tetratricopeptide repeat (TPR) domain from the catalytic domain, these results indicate that the TPR domain shields the active site. Polyunsaturated fatty acids, such as arachidonic acid, and lipids containing polyunsaturated fatty acids, such as phosphatidylinositol, stimulate both bacterially expressed human and native rabbit PP5 activity >25‐fold towards casein and myelin basic protein. Phosphatidylinositol binds to the TPR domain, and not to the catalytic domain, indicating that activation by polyunsaturated fatty acids is allosteric and that it may occur by movement of the TPR domain to allow substrate access.