National Natural Science Foundation of China (NSFC)
中国
引用
ジャーナル: Nat Commun / 年: 2024 タイトル: Architecture and activation of human muscle phosphorylase kinase. 著者: Xiaoke Yang / Mingqi Zhu / Xue Lu / Yuxin Wang / Junyu Xiao / 要旨: The study of phosphorylase kinase (PhK)-regulated glycogen metabolism has contributed to the fundamental understanding of protein phosphorylation; however, the molecular mechanism of PhK remains ...The study of phosphorylase kinase (PhK)-regulated glycogen metabolism has contributed to the fundamental understanding of protein phosphorylation; however, the molecular mechanism of PhK remains poorly understood. Here we present the high-resolution cryo-electron microscopy structures of human muscle PhK. The 1.3-megadalton PhK αβγδ hexadecamer consists of a tetramer of tetramer, wherein four αβγδ modules are connected by the central β scaffold. The α- and β-subunits possess glucoamylase-like domains, but exhibit no detectable enzyme activities. The α-subunit serves as a bridge between the β-subunit and the γδ subcomplex, and facilitates the γ-subunit to adopt an autoinhibited state. Ca-free calmodulin (δ-subunit) binds to the γ-subunit in a compact conformation. Upon binding of Ca, a conformational change occurs, allowing for the de-inhibition of the γ-subunit through a spring-loaded mechanism. We also reveal an ADP-binding pocket in the β-subunit, which plays a role in allosterically enhancing PhK activity. These results provide molecular insights of this important kinase complex.