This family consists of several eukaryotic L6 membrane proteins. 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 it has now been found that that they are not significantly related to genuine tetraspanins, but instead constitute their own L6 family [1]. Several members of this family have been implicated in human cancer [2,3].

1: The L6 membrane proteins--a new four-transmembrane superfamily. Wright MD, Ni J, Rudy GB; Protein Sci 2000;9:1594-1600. PMID:10975581

2: Cloning and expression of the tumor-associated antigen L6. Marken JS, Schieven GL, Hellstrom I, Hellstrom KE, Aruffo A; Proc Natl Acad Sci U S A 1992;89:3503-3507. PMID:1565644

3: Identification of a new tumour-associated antigen TM4SF5 and its expression in human cancer. Muller-Pillasch F, Wallrapp C, Lacher U, Friess H, Buchler M, Adler G, Gress TM; Gene 1998;208:25-30. PMID:9479038