Intracellular Loop 2 Peptides of the Human 5HT1a Receptor are Differential Activators of Gi

[Novel achievements in development and application of GPCR-peptides]

One of the approaches to creating the regulators of G-protein-coupled receptors (GPCR) is the development of peptides that structurally correspond to the functionally important regions of the intracellular extracellular loops of the receptors. GPCR-peptides can selectively regulate the functional activity of homologous receptor and affect the hormonal signal transduction via the receptor. Among the peptides corresponding to the intracellular regions of GPCR, their derivatives modified with hydrophobic radicals exhibit the highest activity and selectivity of action in vitro and in vivo. Ample evidence demonstrates that lipophilic GPCR-peptides may be used to treat diseases and various abnormalities that depend on the functional activity of receptors homologous to them. In turn, the peptides corresponding to the extracellular regions of GPCR can be used as functional probes for studying the specific interaction between the receptors and their ligands, as well as for studying the etiology and pathogenesis of autoimmune diseases caused by the production of antibodies to GPCR antigenic determinants that are localized in the receptor extracellular loops. The present review focuses on the recent achievements in development and application of GPCR-peptides and on the prospects for their further use in medicine and fundamental biology.

[Prospects for use of peptides and their derivatives, structurally corresponding to the G protein-coupled receptors, in medicine]

The regulation of signaling pathways involved in the control of many physiological functions is carried out via the heterotrimeric G protein-coupled receptors (GPCR). The search of effective and selective regulators of GPCR and intracellular signaling cascades coupled with them is one of the important problems of modern fundamental and clinical medicine. Recently data suggest that synthetic peptides and their derivatives, structurally corresponding to the intracellular and transmembrane regions of GPCR, can interact with high efficiency and selectivity with homologous receptors and influence, thus, the functional activity of intracellular signaling cascades and fundamental cellular processes controlled by them. GPCR-peptides are active in both in vitro and in vivo. They regulate hematopoiesis, angiogenesis and cell proliferation, inhibit tumor growth and metastasis, and prevent the inflammatory diseases and septic shock. These data show greatest prospects in the development of the new generations of drugs based on GPCR-derived peptides, capable of regulating the important functions of the organism.