cAMP (3',5' cyclic adenosine monophosphate) is a second messenger that in
eukaryotic cells induces physiological responses ranging from growth, differentiation,
and gene expression to secretion and neurotransmission. Most of these effects have
been attributed to the binding of cAMP to cAMP-dependent protein kinase A (PKA).
Kawasaki et al 1998 isolated a family of cAMP-binding proteins that are differentially distributed in the
mammalian brain and body organs and that exhibit both cAMP-binding and guanine
nucleotide exchange factor (GEF) domains is reported. These cAMP-regulated GEFs
(cAMP-GEFs) bind cAMP and selectively activate the Ras superfamily guanine
nucleotide binding protein Rap1A in a cAMP-dependent but PKA-independent manner.
General function
Intracellular signaling cascade
Comment
The cAMP-GEF proteins have similar domain structures, with a cAMP-binding domain at the NH2 terminus, a GEF domain at the COOH terminus, and a link region in between. These mammalian proteins show strong structural similarity to a predicted open reading frame (T20G5.5) in Caenorhabditis elegans (cel cAMP-GEF).
The cAMP-binding domains of cAMP-GEF family proteins form a distinct group within the cyclic nucleotide-binding protein superfamily, with closest similarity to the B domains of PKA regulatory subunits Kawasaki et al 1998 .
Cellular localization
Cytoplasmic
Comment
Ovarian function
Follicle development
Comment
Kawasaki et al 1998 reported that cAMP-GEFI was widely expressed, whereas cAMP-GEFII was prominent in the brain and the adrenal
glands. Both genes were expressed in the ovary.