ROCK2 is a serine/threonine protein kinase that serves as a critical regulator of actin cytoskeleton dynamics and cell contractility through phosphorylation of multiple effector proteins including MYL9 and other cytoskeletal regulators. The kinase controls diverse cellular processes including stress fiber formation, focal adhesion assembly, and cell migration 1. Beyond cytoskeletal regulation, ROCK2 modulates immune homeostasis by regulating the balance between pro-inflammatory Th17 cells and anti-inflammatory regulatory T cells via STAT3/STAT5 signaling 2, and functions as a negative regulator of angiogenesis 3. ROCK2 plays pathological roles in multiple diseases: chr2 graft-versus-host disease (cGVHD), where selective ROCK2 inhibition with belumosudil achieves 74-77% overall response rates with durable remissions 24; liver fibrosis, where endothelial and perivascular ROCK2 upregulation promotes pro-fibrotic signaling 3; skin fibrosis, where ROCK2 operates downstream of the mechanotransducer TAGLN to regulate glucose metabolism and fibroblast contractility 1; and allergic asthma, where SUMOylation-mediated ROCK2 activation drives goblet cell metaplasia 5. Additionally, ROCK2-mediated pericyte contractility impairs tumor vasculature function 6, and ROCK2 regulates epithelial barrier integrity through claudin-1 expression 7 and inflammatory responses in epidermis via adherens junction disruption 8. These findings establish ROCK2 as a therapeutically targetable kinase across fibrotic, inflammatory, and immune disorders.