Persistent fibroblast activation and myofibroblast phenoconversion underlying multi-organ fibrosis in systemic sclerosis have been associated with high expression and activity of CDK5 and its CDK5R1 subunit p35.556 The authors demonstrate that CDK5 activity stimulates collagen production and myofibroblast markers, whereas CDK5 knockdown abrogated TGF-β fibrotic responses, suggesting that selective pharmacological targeting of CDK5 might represent a successful approach to treat fibrosis.556. The gene discussed is CDK5; the disease is systemic sclerosis.