The FXYD gene family of small ion transport regulators or channels: cDNA sequence, protein signature sequence, and expression

A gene family of small membrane proteins, represented by phospholemman and the gamma subunit of Na,K-ATPase, was defined and characterized by the anal ysis of more than 1000 related ESTs (expressed sequence tags). In addition to new and more complete cDNA sequence for known family members (including MAT-8, CHIF, and RIC), the findings included two new family members and new splicing variants. A large number of EST replicates made it possible to de rive curated DNA sequence with higher confidence and accuracy than from the sequencing of individual clones. The family has a core motif of 35 invaria nt and conserved amino acids centered on a single transmembrane span. Featu res of each predicted protein product were compared, and tissue distributio ns were determined. The gene family was named FXYD (pronounced fix-id) in r ecognition of invariant amino acids in its signature motif, The abundant pr oteins are involved in the control of ion transport. (C) 2000 Academic Pres s.