Regulation of cAMP-mediated signal transduction via interaction of caveolins with the catalytic subunit of protein kinase A

Babak Razani, Charles S. Rubin, Michael P. Lisanti

Research output: Contribution to journalArticle

146 Citations (Scopus)

Abstract

cAMP-dependent processes are essential for cell growth, differentiation, and homeostasis. The classic components of this system include the serpentine receptors, heterotrimeric G-proteins, adenylyl cyclase, protein kinase A (PKA), and numerous downstream target substrates. Evidence is accumulating that some members of this cascade are concentrated within membrane microdomains, termed caveolae and caveolae-related domains. In addition, the caveolin-1 protein has been shown to interact with some of these components, and this interaction inhibits their enzymatic activity. However, the functional effects of caveolins on cAMP-mediated signaling at the most pivotal step, PKA activation, remain unknown. Here, we show that caveolin-1 can dramatically inhibit cAMP-dependent signaling in vivo. We provide evidence for a direct interaction between caveolin-1 and the catalytic subunit of PKA both in vitro and in vivo. Caveolin-1 binding appears to be mediated both by the caveolin scaffolding domain (residues 82-101) and a portion of the C-terminal domain (residues 135-156). Further functional analysis indicates that caveolin-based peptides derived from these binding regions can inhibit the catalytic activity of purified PKA in vitro. Mutational analysis of the caveolin scaffolding domain reveals that a series of aromatic residues within the caveolin scaffolding domain are critical for mediating inhibition of PKA. In addition, co-expression of caveolin-1 and PKA in cultured cells results in their co-localization as seen by immunofluorescence microscopy. In cells co-expressing caveolin-1 and PKA, PKA assumed a punctate distribution that coincided with the distribution of caveolin-1. In contrast, in cells expressing PKA alone, PKA was localized throughout the cytoplasm and yielded a diffuse staining pattern. Taken together, our results suggest that the direct inhibition of PKA by caveolin-1 is an important and previously unrecognized mechanism for modulating cAMP- mediated signaling.

Original languageEnglish (US)
Pages (from-to)26353-26360
Number of pages8
JournalJournal of Biological Chemistry
Volume274
Issue number37
DOIs
StatePublished - Sep 10 1999

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Cyclic AMP-Dependent Protein Kinase Catalytic Subunits
Caveolins
Signal transduction
Caveolin 1
Cyclic AMP-Dependent Protein Kinases
Signal Transduction
Caveolae
Cells
Membrane Microdomains
Heterotrimeric GTP-Binding Proteins
Functional analysis
Cell growth
Fluorescence Microscopy
Adenylyl Cyclases
Cell Differentiation
Cultured Cells
Catalyst activity
Microscopic examination
Cytoplasm
Homeostasis

ASJC Scopus subject areas

  • Biochemistry

Cite this

Regulation of cAMP-mediated signal transduction via interaction of caveolins with the catalytic subunit of protein kinase A. / Razani, Babak; Rubin, Charles S.; Lisanti, Michael P.

In: Journal of Biological Chemistry, Vol. 274, No. 37, 10.09.1999, p. 26353-26360.

Research output: Contribution to journalArticle

Razani, Babak ; Rubin, Charles S. ; Lisanti, Michael P. / Regulation of cAMP-mediated signal transduction via interaction of caveolins with the catalytic subunit of protein kinase A. In: Journal of Biological Chemistry. 1999 ; Vol. 274, No. 37. pp. 26353-26360.
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