Src homology 3 domain of SAM And SH3 Domain Containing Proteins
This subfamily, also called the SLY family, is composed of SAM And SH3 Domain Containing Protein 1 (SASH1), SASH2, SASH3, and similar proteins. These are adaptor proteins containing a central conserved region with a bipartite nuclear localization signal (NLS) as wells as SAM (sterile alpha motif) and SH3 domains. SASH1 is a potential tumor suppressor in breast and colon cancer. It is widely expressed in normal tissues (except lymphocytes and dendritic cells) and is localized in the nucleus and the cytoplasm. SASH1 interacts with the oncoprotein cortactin and is important in cell migration and adhesion. SASH2 (also called SAMSN-1, SLY2, HACS1 or NASH1) and SASH3 (also called SLY/SLY1) are expressed mainly in hematopoietic cells, although SASH2 is also found in endothelial cells as well as myeloid leukemias and myeloma. SASH2 was found to be differentially expressed in malignant haematopoietic cells and in colorectal tumors, and is a potential tumor suppressor in lung cancer. SASH3 is essential in the full activation of adaptive immunity and is involved in the signaling of T cell receptors. SH3 domains are protein interaction domains that bind to proline-rich ligands with moderate affinity and selectivity, preferentially to PxxP motifs. They play versatile and diverse roles in the cell including the regulation of enzymes, changing the subcellular localization of signaling pathway components, and mediating the formation of multiprotein complex assemblies.
Jiyao W et al.(2023). "The conserved domain database in 2023.",