Signal transducing adapter molecule 2

Signal transducing adapter molecule 2 (STAM2) is a 525-amino acid cytoplasmic protein that acts as an adaptor in intracellular signal transduction cascades initiated by cytokines and growth factors, particularly IL-2 and GM-CSF (UniProt: O75886). It participates in T-cell development and DNA synthesis pathways, and forms part of the ESCRT-0 complex with HGS, where it recognizes ubiquitinated receptor tyrosine kinases and directs them to multivesicular bodies for lysosomal degradation.

STAM2 functions in endocytic trafficking and receptor downregulation, processes critical for cellular signaling homeostasis. No inherited disease associations are documented in UniProt for this protein.

STAM2 is marked as downregulated in Alzheimer's disease, with a mean log2 fold-change of −0.88 in post-mortem AD brain tissue compared to age-matched controls (Chaparral AD proteomics). This reduction was detected across a single subcellular fraction in a TMT-labeled proteomics experiment examining four fractions (P2, P3, S2, S3). The functional significance of decreased STAM2 levels in AD pathogenesis remains to be clarified.