Phosphorylation by glycogen synthase kinase of inhibitor-2 does not change its structure in free state.
Inhibitor-2 (I2) is a thermostable protein that specifically binds to the catalytic subunit of protein phosphatase-1 (PP1), resulting in the formation of the inactive holoenzyme, ATP-Mg-dependent phosphatase. Phosphorylation of I2 at Thr-72 by glycogen synthase kinase-3 (GSK-3) results in activation of the phosphatase, suggesting that kinase action triggers conformational change in the complex. In this paper, we characterize the effect of GSK-3 phosphorylation on the structure of free state I2[1-172] by nuclear magnetic resonance and circular dichroism spectroscopy, and show that phosphorylation has no significant effect on its conformation. We conclude that the conformational changes of ATP-Mg-dependent phosphatase induced by GSK-3 phosphorylation must depend on the interactions between PP1 and I2.
Lin
Ta-Hsien
TH
Institute of Biochemistry, National Yang-Ming University, and Department of Medical Research and Education, Taipei Veterans General Hospital, Shih-pai, Taipei 112, Taiwan, ROC.
Chen
Yi-Chen
YC
Chyan
Chia-lin
CL
Tsay
Li-huang
LH
Tang
Tzu Chun
TC
Jeng
Hao-Hsuan
HH
Lin
Fang-Min
FM
Huang
Hsien-bin
HB
D000818:Animals; D002942:Circular Dichroism; D004926:Escherichia coli / Q000378:metabolism; D038362:Glycogen Synthase Kinase 3 / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007527:Isoenzymes; D019906:Nuclear Magnetic Resonance, Biomolecular / Q000379:methods; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation; D011487:Protein Conformation; D054645:Protein Phosphatase 1; D011506:Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013912:Threonine / Q000378:metabolism; D000097847:Protein Phosphatase Inhibitory Proteins
D038362:Glycogen Synthase Kinase 3; D007527:Isoenzymes; D010749:Phosphoprotein Phosphatases; D054645:Protein Phosphatase 1; D011506:Proteins; D011994:Recombinant Proteins; D013912:Threonine; C024833:protein phosphatase inhibitor-2; D000097847:Protein Phosphatase Inhibitory Proteins