RT Journal Article
SR Electronic
T1 Structural Determinants Required for the Bioactivities of Prokineticins and Identification of Prokineticin Receptor Antagonists
JF Molecular Pharmacology
JO Mol Pharmacol
FD American Society for Pharmacology and Experimental Therapeutics
SP 582
OP 588
DO 10.1124/mol.65.3.582
VO 65
IS 3
A1 Clayton M. Bullock
A1 Jia-Da Li
A1 Qun-Yong Zhou
YR 2004
UL http://molpharm.aspetjournals.org/content/65/3/582.abstract
AB Prokineticins are cysteine-rich secreted proteins that regulate diverse biological processes, including gastrointestinal motility, angiogenesis, and circadian rhythms. Two closely related G protein-coupled receptors that mediate signal transduction of prokineticins have recently been cloned. The structural elements required for prokineticins' bioactivities are still unknown. We show here that both the N-terminal hexapeptide (AVITGA) and C-terminal cysteine-rich domains are critical for the bioactivities of prokineticins. Substitutions, deletions, and insertions to the conserved N-terminal hexapeptides result in the loss of agonist activity. Mutant prokineticins with the substitution of the first N-terminal alanine with methionine or the addition of a methionine to the N terminus inhibit the activation of prokineticin receptors and thus are considered as antagonists of prokineticin receptors. We have further shown that mutations in selected cysteine residues in the C-terminal domain result in prokineticins without biological activity. The essential role of C-terminal domain is reinforced by two observations: that peptides without the carboxyl domain and proteins with the N-terminal hexapeptide fused to the carboxyl domains of colipase or dickkopf are devoid of biological activity. We demonstrate that limited structural changes of C-terminal cysteine-rich regions of prokineticins are tolerable because chimeric prokineticins with swapped cysteine-rich domains between prokineticin 1 and prokineticin 2, as well as a splice variant of prokineticin 2 that contains extra 21 residue insertion in its C-terminal domain, are biologically active.