SAM and SH3 domain-containing protein 3 (SASH3)

SAM and SH3 domain-containing protein 3 (SASH3) is a lymphoid-specific adaptor protein containing sterile alpha motif (SAM) and Src homology 3 (SH3) domains, primarily expressed in lymphocytes[1][3][5]. It organizes signaling complexes and mediates propagation of signal transduction cascades within immune cells, especially T cells[1][3][5]. SASH3 is essential for proper T-cell activation, proliferation, progression through the cell cycle, and survival; its deficiency results in defective immune responses, indicated by impaired T and B cell proliferation, increased apoptosis, and immune dysregulation[1][2][3][5]. Genetic mutations in SASH3 cause a novel X-linked combined immunodeficiency syndrome characterized by recurrent infections, multilineage cytopenias (such as autoimmune hemolytic anemia and immune thrombocytopenia), CD4+ T cell lymphopenia, and features of autoimmunity[1][3][5]. Patient and mouse model studies demonstrate that SASH3 is required for intact T and natural killer cell function, and its deficiency can be rescued by gene correction or potentially bone marrow transplant[1][3][5]. There are currently no known drugs directly targeting SASH3, and it is primarily under investigation as a rare monogenic immunodeficiency gene rather than as a traditional therapeutic drug target[1][3][5]. Key references: [1][2][3][5].

Other names

HACS2753P9CXorf9SH3D6CSLYSLY1SH3-containing lymphocyte proteinSAM and SH3 domain-containing 3SH3 protein expressed in lymphocytes homolog