CNN1 (calponin 1) is a thin filament-associated protein primarily expressed in smooth muscle cells that regulates contractility through inhibition of actin-activated myosin ATPase activity 1. As an actin-binding protein, CNN1 stabilizes the actin cytoskeleton and fine-tunes smooth muscle contractility 1. The protein interacts with actin, calmodulin, and tropomyosin to modulate contraction dynamics 1. Beyond its classical smooth muscle role, CNN1 is expressed in vascular myofibroblasts and stromal cells associated with disease pathology. In atherosclerosis, CNN1 marks smooth muscle cell contractile phenotype; DT-109 treatment upregulated CNN1 expression while suppressing atherosclerotic lesion formation and calcification in nonhuman primates 2. CNN1 serves as a novel prognostic marker in colon cancer-associated stromal cells, where elevated expression correlates with poor patient outcomes 3. Recent mechanistic studies reveal CNN1 participates in epigenetic regulation: the Kdm6a-CNN1 axis controls microvascular endothelial cell senescence and inflammation following spinal cord injury, with CNN1 deletion reducing senescence-associated inflammatory factor secretion and improving neurological recovery 4. In adenomyosis, CNN1+ stromal fibroblasts promote fibrosis through fibroblast-to-myofibroblast transition 5. NKX2-5 suppresses CNN1 expression during pathological vascular remodeling in pulmonary arterial hypertension 6. These findings establish CNN1 as a multifunctional regulator linking smooth muscle biology to disease-relevant cellular differentiation and inflammation.