This family is a family of eukaryotic membrane proteins. It was previously annotated as including a putative receptor for human cytomegalovirus gH [1] but this has has since been disputed [2]. Analysis of the mouse Tapt1 protein (transmembrane anterior posterior transformation 1) has shown it to be involved in patterning of the vertebrate axial skeleton.

1: Cloning and epitope mapping of a functional partial fusion receptor for human cytomegalovirus gH. Baldwin BR, Zhang CO, Keay S; J Gen Virol 2000;81:27-35. PMID:10640539

2: Mutation of a ubiquitously expressed mouse transmembrane protein (Tapt1) causes specific skeletal homeotic transformations. Howell GR, Shindo M, Murray S, Gridley T, Wilson LA, Schimenti JC; Genetics. 2007;175:699-707. PMID:17151244