The L6 membrane proteins—A new four‐transmembrane superfamily

Abstract
L6, IL‐TMP, and TM4SF5 are cell surface proteins predicted to have four transmembrane domains. Previous sequence analysis led to their assignment as members of the tetraspanin superfamily. In this paper, we identify a new sequence (L6D) that is strikingly similar to L6, IL‐TMP, and TM4SF5. Analyses of these four sequences indicate that they are not significantly related to genuine tetraspanins, but instead constitute their own L6 superfamily.