MYH9, encoding the heavy chain of non-muscle myosin IIA, is a cytoplasmic myosin crucial for intracellular chemomechanical force generation and actin cytoskeleton translocation. Its functions are regulated by phosphorylation of light and heavy chains and protein-protein interactions. It participates in various biological processes, especially in embryonic development, and is associated with pathways related to cell motility and cytoskeletal regulation [1].

Mutations in MYH9 cause autosomal-dominant MYH9-related diseases, characterized by macrothrombocytopenia, leukocyte inclusions, and risks of renal failure, hearing loss, and cataracts [2,6]. In hepatocellular carcinoma, silencing MYH9 blocks HBx-induced GSK3β ubiquitination and degradation, inhibiting tumor stemness, epithelial-mesenchymal transition, and c-Jun signaling [3]. In gastric cancer, nuclear MYH9 promotes CTNNB1 transcription, conferring anoikis resistance and metastasis [4]. In rheumatoid arthritis, MYH9 is identified as a key regulator for synoviocyte migration and invasion [5]. In serous ovarian cancer, MYH9 combines with MYH10 to recruit USP45, promoting carcinogenesis, progression, and cisplatin resistance [7]. Also, Oviductal Glycoprotein 1 promotes hypertension by interacting with MYH9, leading to vascular remodeling [8].

In conclusion, MYH9 is essential for multiple biological functions related to cell motility and cytoskeletal organization. The study of MYH9 through genetic models, such as gene-knockout mouse models, has revealed its significant roles in various disease conditions including hematological disorders, cancers, and hypertension. Understanding MYH9 functions provides insights into disease mechanisms and potential therapeutic targets.