期刊
JOURNAL OF MOLECULAR BIOLOGY
卷 412, 期 2, 页码 155-164出版社
ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jmb.2011.06.041
关键词
NMR; conformational selection; PKA; phosphorylation kinetics
资金
- National Institutes of Health [GM72701, T32DE007288]
- Midwest Affiliate American Heart Association [10PRE3860050]
Phosphorylation of membrane proteins is a central regulatory and signaling mechanism across cell compartments. However, the recognition process and phosphorylation mechanism of membrane-bound substrates by kinases are virtually unknown. cAMP-dependent protein kinase A (PICA) is a ubiquitous enzyme that phosphorylates several soluble and membrane-bound substrates. In cardiomyocytes, PICA targets phospholamban (PLN), a membrane protein that inhibits the sarcoplasmic reticulum Ca2+-ATPase (SERCA). In the unphosphorylated state, PLN binds SERCA, reducing the calcium uptake and generating muscle contraction. PKA phosphorylation of PLN at S16 in the cytoplasmic helix relieves SERCA inhibition, initiating muscle relaxation. Using steady-state kinetic assays, NMR spectroscopy, and molecular modeling, we show that PKA recognizes and phosphorylates the excited, membrane-detached R-state of PLN. By promoting PLN from a ground state to an excited state, we obtained a linear relationship between rate of phosphorylation and population of the excited state of PLN. The conformational equilibrium of PLN is crucial to regulate the extent of PLN phosphorylation and SERCA inhibition., (C) 2011 Published by Elsevier Ltd.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据