PKA-RII subunit phosphorylation precedes activation by cAMP and regulates activity termination
Abstract
Type II isoforms of cyclic adenosine monophosphate (cAMP)–dependent protein kinase A (PKA-II) contain a phosphorylatable epitope within the inhibitory domain of RII subunits (pRII) with still unclear function. In vitro, RII phosphorylation occurs in the absence of cAMP, whereas staining of cells with pRII-specific antibodies revealed a cAMP-dependent pattern. In sensory neurons, we found that increased pRII immunoreactivity reflects increased accessibility of the already phosphorylated RII epitope during cAMP-induced opening of the tetrameric RII2:C2 holoenzyme. Accordingly, induction of pRII by cAMP was sensitive to novel inhibitors of dissociation, whereas blocking catalytic activity was ineffective. Also in vitro, cAMP increased the binding of pRII antibodies to RII2:C2 holoenzymes. Identification of an antibody specific for the glycine-rich loop of catalytic subunits facing the pRII-epitope confirmed activity-dependent binding with similar kinetics, proving that the reassociation is rapid and precisely controlled. Mechanistic modeling further supported that RII phosphorylation precedes cAMP binding and controls the inactivation by modulating the reassociation involving the coordinated action of phosphodiesterases and phosphatases.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Apr 03, 2018
- Source ID
- 10.1083/jcb.201708053
Entities
People
- Frank Schwede
- Friedrich W. Herberg
- Hanna Hammerich
- Humberto Gonczarowska-jorge
- Jan Hasenauer
- Joerg Isensee
- Matthias J Knape
- Melanie Kaufholz
- René P. Zahedi
- Tim Hucho
Organizations
- Biolog Life Science Institute
- Coordenação de Aperfeicoamento de Pessoal de Nível Superior
- Federal Ministry of Research, Technology and Space
- Helmholtz Zentrum München
- Institute of Space and Astronautical Science
- Technical University of Munich
- The Michael J. Fox Foundation
- U.S. Army Center for Environmental Health Research
- Uniklinik Köln
- University of Kassel