Avtor/Urednik		Oestlund, Pernilla; Kilk, Kalle; Lindgren, Maria; Haellbrink, Mattias; Jiang, Yang; Budihna, Metka; Černe, Katarina; Bavec, Aljoša; Oestenson, Claes-Goran; Zorko, Matjaž
Naslov		Cell-penetrating mimics of agonist-activated G-protein coupled receptors
Tip		članek
Vir		Int J Pept Res Ther
Vol. in št.		Letnik 11, št. 4
Leto izdaje		2005
Obseg		str. 237-47
Jezik		eng
Abstrakt		Cell-penetrating peptides have proven themselves as valuable vectors for intracellular delivery. Relatively little is known about the frequency of cell-penetrating sequences in native proteins and their functional role. By computational comparison of peptide sequences, we recently predicted that intracellular loops of G-protein coupled receptors (GPCR) have high probability for occurrence of cell-penetrating motifs. Since the loops are also receptor and G-protein interaction sites, we postulated that the short cell-penetrating peptides, derived from GPCR, when applied extracellularly can pass the membrane and modulate G-protein activity similarly to parent receptor proteins. Two model systems were analyzed as proofs of the principle. A peptide based on the C-terminal intracellular sequence of the rat angiotensin receptor (AT1AR) is shown to internalize into live cells and elicit blood vessel contraction even in the presence of AT1AR antagonist Sar1-Thr8-angiotensin II. The peptide interacts with the same selectivity towards G-protein subtypes as agonist-activated AT1AR and blockade of phospholipase C abolishes its effect. Another cell-penetrating peptide, G53-2 derived from human glucagon-like peptide receptor (GLP-1R) is shown to induce insulin release from isolated pancreatic islets. The mechanism was again found to be shared with the original GLP-1R, namely G11-mediated inositol 1,4,5-triphosphate release pathway. These data reveal a novel possibility to mimic the effects of signalling transmembrane proteins by application of shorter peptide fragments.
Deskriptorji		GTP-BINDING PROTEINS GTP PHOSPHOHYDROLASE BINDING SITES INOSITOL 1,4,5-TRISPHOSPHATE ANGIOTENSINS RATS SIGNAL TRANSDUCTION SWINE RECEPTORS, ANGIOTENSIN RECEPTORS, GLUCAGON AMINO ACID SEQUENCE TRANSLOCATION (GENETICS) INSULIN VASOCONSTRICTION TUMOR CELLS, CULTURED MICROSCOPY, FLUORESCENCE FLUOROMETRY