Family 2.A.50 - The Glycerol Uptake Family       

Family ID: 53377

Yeast can use glycerol both as a carbon source and as an osmolyte. In Saccharomyces cerevisiae, glycerol is actively taken up via two electrogenic H+ symporters, GUP1 (YGL084c) and GUP2 (YPL189w). These proteins are the first characterized members in a moderately sized family of polytopic integral membrane proteins from yeast, fungi, animals and bacteria. Several of the bacterial proteins have been implicated in extracellular polysaccharide modification. One such protein, DltB (spP39580) has been implicated in the transport of activated D-alanine across the bacterial cytoplasmic membrane for biosynthesis of D-alanine lipoteichoic acid. It is possible that proteins implicated in polysaccharide modification serve a similar role. Most of these proteins are of between 450 and 610 aas in length and exhibit 8-10 putative TMSs. One protein (spO09758) from Schizosaccharomyces pombe is half sized, having only 231aas with 4-5 putative TMSs.