Background: Chemerin (chem163S) is proteolytically cleaved to generate active isoforms. Results: Chem157S has the highest activity in stimulating calcium transients and chemotaxis, chem158K and chem163S have much lower activity, and chem155A is not an agonist. Chem157S stimulates signaling in glioblastoma cells. Conclusion: Chem163S proteolysis to chem157S is needed for its activity. Significance: Chemerin may play a role in glioblastoma.