SFLLR is a peptide agonist of protease-activated receptor type 1 (PAR1, also known as the thrombin receptor) that induces platelet adhesion and aggregation, mimicking the effects of thrombin. SFLLR exhibits pro-thrombotic, pro-angiogenic, and pro-inflammatory activities. In vagal motor neurons, SFLLR induces apoptosis. SFLLR increases release of pro-matrix metalloproteinase 9 (pro-MMP9) from fibroblasts in a JAK/STAT3-dependent manner; it also increases expression of matrix metalloproteinase 2 (MMP2) and induces angiogenesis in endothelial cells. SFLLR increases release of IL-6 from T cells as well. Additionally, this peptide can increase Na+ current in cardiomyocytes.