※ Axl family introduction

    Axl family also refer to TAM family which consists of Tyro-3, Axl and Mer. TAM family are receptor tyrosine kinases characterized by a conserved sequence within the kinase domain and adhesion molecule-like extracellular domains. The sequence analysis shows that TAM kinase share 31%-36% identical amino acids within the extracellular region and 54%-59% identity within intracellular domain. TAM kinase can produce diverse cellular functions via combining with different ligand and in different cell types. The loss of TAM receptor in macrophages/dendritic cells will lead to autoimmune diseases including rheumatoid arthritis and lupus. In Nautre killer cells (NK cells), TAM receptor is essential for normal differentiation and functional maturation of NK cells. In platelets, TAM receptor is required for platelets aggregation. TAM kinases also executive function via several signaling pathway. MER and Axl signaling lead to platelet aggregation, cell survial, regulation of proinflammatory ctyokine production and regulation of the actin cytoskeleton. Tyro-3 signaling pathway also mediates the cell transformation and osteoclastic bone resorption. Mutation or abnormal expression of TAM kinases will cause some diseases, and several studies have validated the therapeutic potential of targeting the TAM family in cancer therapy (1).

Reference
1. Linger, R.M., Keating, A.K., Earp, H.S. and Graham, D.K. (2008) TAM receptor tyrosine kinases: biologic functions, signaling, and potential therapeutic targeting in human cancer. Adv Cancer Res, 100, 35-83. PMID: 18620092