Connecting cAMP and Ras Superfamily Signaling

Science  18 Dec 1998:
Vol. 282, Issue 5397, pp. 2149
DOI: 10.1126/science.282.5397.2149s

Activation of many receptors on the cell surface results in generation of the “second messenger” molecule cAMP (adenosine 3′-5′ monophosphate). Most of the biological effects of cAMP result from activation of the cAMP-dependent protein kinase. Kawasaki et al. (p. 2275) found evidence for another mechanism by which signals may be generated in response to cAMP. They identified a family of guanine nucleotide exchange proteins (cAMP-GEFs) that are particularly abundant in brain and that bind cAMP. Binding of cAMP activated the exchange activity of the cAMP-GEFs and resulted in selective activation of Rap1A, a member of the Ras superfamily of guanine nucleotide binding proteins. The cAMP-GEFS appear to connect signaling pathways that generate cAMP to those mediated by members of the Ras superfamily.

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