Association of dystrobrevin and regulatory subunit of protein kinase A: a new role for dystrobrevin as a scaffold for signaling proteins.
The dystrophin-related and -associated protein dystrobrevin is a component of the dystrophin-associated protein complex, which directly links the cytoskeleton to the extracellular matrix. It is now thought that this complex also serves as a dynamic scaffold for signaling proteins, and dystrobrevin may play a role in this context. Since dystrobrevin involvement in signaling pathways seems to be dependent on its interaction with other proteins, we sought new insights and performed a two-hybrid screen of a mouse brain cDNA library using beta-dystrobrevin, the isoform expressed in non-muscle tissues, as bait. Among the positive clones characterized after the screen, one encodes the regulatory subunit RIalpha of the cAMP-dependent protein kinase A (PKA). We confirmed the interaction by in vitro and in vivo association assays, and mapped the binding site of beta-dystrobrevin on RIalpha to the amino-terminal region encompassing the dimerization/docking domain of PKA regulatory subunit. We also found that the domain of interaction for RIalpha is contained in the amino-terminal region of beta-dystrobrevin. We obtained evidence that beta-dystrobrevin also interacts directly with RIIbeta, and that not only beta-dystrobrevin but also alpha-dystrobrevin interacts with PKA regulatory subunits. We show that both alpha and beta-dystrobrevin are specific phosphorylation substrates for PKA and that protein phosphatase 2A (PP2A) is associated with dystrobrevins. Our results suggest a new role for dystrobrevin as a scaffold protein that may play a role in different cellular processes involving PKA signaling.
Ceccarini
Marina
M
Department of Cell Biology and Neuroscience, Istituto Superiore di Sanità, 00161 Roma, Italy.
Grasso
Margherita
M
Veroni
Caterina
C
Gambara
Guido
G
Artegiani
Benedetta
B
Macchia
Gianfranco
G
Ramoni
Carlo
C
Torreri
Paola
P
Mallozzi
Cinzia
C
Petrucci
Tamara C
TC
Macioce
Pompeo
P
D000818:Animals; D001665:Binding Sites; D001921:Brain / Q000378:metabolism; D019556:COS Cells; D002522:Chlorocebus aethiops; D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D017868:Cyclic AMP-Dependent Protein Kinases / Q000737:chemistry*; D049029:Dystrophin-Associated Proteins / Q000737:chemistry* / Q000502:physiology*; D005109:Extracellular Matrix; D011485:Protein Binding; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D051381:Rats; D015398:Signal Transduction; D020798:Two-Hybrid System Techniques
D054756:Cyclic AMP-Dependent Protein Kinase RIalpha Subunit; D049029:Dystrophin-Associated Proteins; C517835:Prkar1a protein, mouse; C517836:Prkar1a protein, rat; C098885:dystrobrevin; D017868:Cyclic AMP-Dependent Protein Kinases