Part of TspanC8 subgroup, composed of 6 members that interact with the transmembrane metalloprotease ADAM10. This interaction is required for ADAM10 exit from the endoplasmic reticulum and for enzymatic maturation and trafficking to the cell surface as well as substrate specificity. Different TspanC8/ADAM10 complexes have distinct substrates (PubMed:26686862, PubMed:28600292, PubMed:37516108). Promotes ADAM10-mediated cleavage of CD44 (PubMed:26686862). Seems to regulate VE-cadherin expression in endothelial cells probably through interaction with ADAM10, promoting leukocyte transmigration (PubMed:28600292).