Structural component of specialized membrane microdomains known as tetraspanin-enriched microdomains (TERMs), which act as platforms for receptor clustering and signaling. Participates thereby in diverse biological functions such as cell signal transduction, adhesion, migration and protein trafficking (PubMed:30066932, PubMed:30291375). Regulates neuronal differentiation in response to NGF by facilitating NGF-mediated activation of NTRK1/TRKA receptor tyrosine kinase and subsequent downstream signaling pathways (By similarity). Plays a role in the inhibition of TNFalpha-induced apoptosis. Mechanistically, inhibits the NF-kappa-B signaling pathway by blocking phosphorylation of CHUK (PubMed:30291375). Also promotes the stability of the thiamine transporter 1/SLC19A2 in intestinal epithelial cells leading to an increase of thiamine uptake process (PubMed:21836059). {ECO:0000250|UniProtKB:Q6AYR9, ECO:0000269|PubMed:21836059, ECO:0000269|PubMed:30066932, ECO:0000269|PubMed:30291375}. This is the function of TSPAN1 (tetraspanin 1, ENSG00000117472).