Mouse Midkine (MK) is a heparin-binding growth factor and cytokine that plays important roles in cell growth, development, and tissue repair in mice (Mus musculus). Midkine is highly expressed during embryonic development and can also be induced in adult tissues in response to injury, inflammation, or physiological stress. Mouse midkine interacts with several cell surface receptors, including receptor-type protein tyrosine phosphatase ζ (PTPRZ1), low-density lipoprotein receptor–related proteins (LRPs), and integrins, activating intracellular signaling pathways such as MAPK, PI3K–AKT, and NF-κB that regulate cell proliferation, migration, survival, and inflammatory responses. Through these mechanisms, midkine contributes to processes including neural development, angiogenesis, immune cell recruitment, and tissue regeneration. In cell culture, recombinant mouse midkine is commonly used to stimulate cell proliferation and migration and to study growth factor–mediated signaling pathways involved in development, inflammation, and tissue repair. Mouse midkine is also widely studied in murine animal models of cancer, inflammatory diseases, and tissue injury to better understand its roles in immune regulation, tumor progression, and regenerative processes.