BACKGROUND: The CEMIP (cell migration–inducing protein) exhibits extremely high expression levels in smooth muscle tissues. However, whether CEMIP modulates the contractile phenotype of vascular smooth muscle cells and confers blood pressure remains elusive. METHODS: To explore the role of CEMIP in SMCs, we generated a mouse model with SMC-specific CEMIP deficiency (SMC-CemipKO). By combining coimmunoprecipitation assay and molecular docking prediction, we identified MLC20 (myosin light chain 20) and its phosphatase, PP1c (protein phosphatase 1c) as binding proteins for CEMIP. To elucidate the mechanism by which CEMIP interacts with MLC20 and PP1c, bioluminescence resonance energy transfer assay and motif mutation were utilized to unravel the intricate network. RESULTS: CEMIP is abundantly expressed in smooth muscle tissues including the mesenteric artery, aorta, and intestine. In a serum-starved contractile phenotype, SMCs responded to serum stimulation by gradually decreasing CEMIP e