Acta Anatomica Sinica ›› 2017, Vol. 48 ›› Issue (6): 761-765.doi: 10.16098/j.issn.0529-1356.2017.06.022

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Progress of the function and mechanism of protein kinase A RⅡβ

DING Yu-jing JIN Xing LIU Jun-xiu MA Fu-rong*   

  1. Department of Otolaryngology Head and Neck Surgery, Peking University Third Hospital, Beijing 100191, China
  • Received:2017-01-09 Revised:2017-05-03 Online:2017-12-06 Published:2017-12-06
  • Contact: MA Fu-rong E-mail:furongma@126.com

Abstract:

Protein kinase A (PKA) exists in mammalian cells as an inactive tetrameric holoenzyme composed of a regulatory (R) subunit dimer and two catalytic (C) subunits. There are four isoforms of the R subunits, RIα, RIβ, RⅡα,and RⅡβ. Each of them has special physicochemical property. RⅡβ subunit contains an N-terminal dimerization/docking domain. PKA is anchored to specific sites in the cell by binding of an adenosine kinase-anchoring protein amphipathic helix to the dimerization/docking domain. At the C terminus there are two tandem highly conserved cyclic nucleotide-binding domains, which relate to depolymerization and activation of the holoenzyme. The heterodimers are anchored together by an interface created by the β4-β5 loop in the RⅡβ subunit. In cells the inactive RⅡβ2:C2 holoenzyme once formed, it may be primed to have its R subunits autophosphory when high availability of cytoplasmic MgATP is given. RⅡβ expression is tissue specific,mainly in the brain, adipose tissue and endocrine organs. Bioinormatics analysis has showed that the sequence of RⅡβis significantly different from other three R subunit isoforms. The big difference indicates that PKA RⅡβ may have special biological function. Therefore many researchers focus on the function and mechanism of PKA RⅡβ.

Key words: Protein kinase A, Regulatory subunit, Allosteric effect, Phosphorylation