Signal transducing adapter molecule 1 is a protein that in humans is encoded by the STAM gene. This gene encodes a member of the signal-transducing adaptor molecule family. These proteins mediate downstream signaling of cytokine receptors and also play a role in ER to Golgi trafficking by interacting with the coat protein II complex. The encoded protein also associates with hepatocyte growth factor-regulated substrate to form the endosomal sorting complex required for transport-0 (ESCRT-0), which sorts ubiquitinated membrane proteins to the ESCRT-1 complex for lysosomal degradation. Alternatively spliced transcript variants have been observed for this gene. [provided by RefSeq].
 Involved in intracellular signal transduction mediated by cytokines and growth factors. Upon IL-2 and GM-CSL stimulation, it plays a role in signaling leading to DNA synthesis and MYC induction. May also play a role in T-cell development. Involved in down-regulation of receptor tyrosine kinase via multivesicular body (MVBs) when complexed with HGS (ESCRT-0 complex). The ESCRT-0 complex binds ubiquitin and acts as sorting machinery that recognizes ubiquitinated receptors and transfers them to further sequential lysosomal sorting/trafficking processes.