TRAP-5 amide, also known as SFLLR-amide, is a protease-activated receptor 1 (PAR 1) agonist peptide[1]. PAR 1 is the primary thrombin-responsive receptor in human cells and plays a significant role in tissue injury responses and related inflammation processes[2]. TRAP-5 amide mimics the action of thrombin and activates the thrombin receptor PAR 1 without the need for proteolysis, making it useful for studying PAR 1 activation mechanisms[3]. TRAP-5 amide is the smallest peptide that can release serotonin from human platelets and retain full activity, with the sequence Ser-Phe-Leu-Leu-Arg-NH2[4].
In vitro, treatment of A549 cells with TRAP-5 amide (10 μM) for 30 minutes under static conditions resulted in a positive dynamic mass redistribution (DMR) similar to that caused by a saturating dose of thrombin (10 units/ml), and this effect lasted for at least 2 hours. Additionally, TRAP-5 amide and thrombin showed mutual cross-desensitization[3].
References:
[1] Ceruso M A, McComsey D F, Leo G C, et al. Thrombin receptor-activating peptides (TRAPs): Investigation of bioactive conformations via structure–activity, spectroscopic, and computational studies[J]. Bioorganic & medicinal chemistry, 1999, 7(11): 2353-2371.
[2] Chen* C, Maryanoff* B E, Andrade-Gordon P. Thrombin receptor modulators: Medicinal chemistry, biological evaluation, and clinical application[J]. Thrombin: Physiology and Disease, 2009: 205-236.
[3] Goral V, Wu Q, Sun H, et al. Label-free optical biosensor with microfluidics for sensing ligand-directed functional selectivity on trafficking of thrombin receptor[J]. FEBS letters, 2011, 585(7): 1054-1060.
[4] Sabo T, Gurwitz D, Motola L, et al. Structure-activity studies of the thrombin receptor activating peptide[J]. Biochemical and biophysical research communications, 1992, 188(2): 604-610.