An Isoform-Specific Myristylation Switch Targets Type II PKA Holoenzymes to Membranes

作者：Zhang, Ping; Ye, Feng; Bastidas, Adam C.; Kornev, Alexandr P.; Wu, Jian; Gin**erg, Mark H.; Taylor, Susan S.^*

来源：Structure, 2015, 23(9): 1563-1572.

DOI：10.1016/j.str.2015.07.007

• DEPENDENT PROTEIN-KINASE
• CATALYTIC SUBUNIT
• ESCHERICHIA-COLI
• N-TERMINUS
• PHOSPHORYLATION
• MYRISTOYLATION
• RI
• DEAMIDATION
• MECHANISM
• SUBSTRATE

Cyclic AMP-dependent protein kinase (PKA) is regulated in part by N-terminal myristylation of its catalytic (C) subunit. Structural information about the role of myristylation in membrane targeting of PKA has been limited. In mammalian cells there are four functionally non-redundant PKA regulatory subunits (RI alpha, RI beta, RII alpha, and RII beta). PKA is assembled as an inactive R2C2 holoenzyme in cells. To explore the role of N-myristylation in membrane targeting of PKA holoenzymes, we solved crystal structures of RI alpha:myrC and RII beta 2: myrC(2), and showed that the N-terminal myristylation site in the myrC serves as a flexible "switch'' that can potentially be mobilized for membrane anchoring of RII, but not RI, holoenzymes. Furthermore, we synthesized nanodiscs and showed by electron microscopy that membrane targeting through the myristic acid is specific for the RII holoenzyme. This membrane-anchoring myristylation switch is independent of A Kinase Anchoring Proteins (AKAPs) that target PKA to membranes by other mechanisms.

• 出版日期2015-9-1