Sterile Alpha Motif Domain Containing Protein 4B (SaMD4B)

The sterile alpha motif (SAM) is a putative protein interaction domain involved in a wide variety of biological processes. SAMD4B, which encodes a putative protein of 694 amino acids with a SAM domain. Northern blot and RT-PCR analysis showed that SAMD4B is widely expressed in human embryonic and adult tissues. Transcriptional activity assays show SAMD4B suppresses transcriptional activity of L8G5-luciferase. Over-expression of SAMD4B in mammalian cells inhibited the transcriptional activities of activator protein-1 (AP-1), p53 and p21, and the inhibitory effects can be relieved by siRNA. Deletion analysis indicates that the SAM domain is the main region for transcriptional suppression. SAMD4B is a widely expressed gene involved in AP-1-, p53-and p21-mediated transcriptional signaling activity.