%0 Journal Article
%T Functional specialization in nucleotide sugar transporters occurred through differentiation of the gene cluster EamA (DUF6) before the radiation of Viridiplantae
%A £¿ke V£¿stermark
%A Markus Alm¨¦n
%A Martin W Simmen
%A Robert Fredriksson
%A Helgi B Schi£¿th
%J BMC Evolutionary Biology
%D 2011
%I BioMed Central
%R 10.1186/1471-2148-11-123
%X We present evidence that the triose-phosphate transporters, domain unknown function 914, uracil-diphosphate glucose-N-acetylglucosamine, and nucleotide sugar transporter families have evolved from a domain duplication event before the radiation of Viridiplantae in the EamA family (previously called domain unknown function 6). We identify previously unknown branches in the solute carrier 30, 35 and 39 protein families that emerged simultaneously as key physiological developments after the radiation of Viridiplantae, including the "35C/E" branch of EamA, which formed in the lineage of T. adhaerens (Animalia). We identify a second cluster of DMTs, called the domain unknown function 1632 cluster, which has non-cytosolic N- and C-termini, and thus appears to have been formed from a different domain duplication event. We identify a previously uncharacterized motif, G-X(6)-G, which is overrepresented in the fifth transmembrane helix of C-terminal domains. We present evidence that the family called fatty acid elongases are homologous to transporters, not enzymes as had previously been thought.The nucleotide sugar transporters families were formed through differentiation of the gene cluster EamA (domain unknown function 6) before Viridiplantae, showing for the first time the significance of EamA.Transmembrane helix (TM) proteins form 27% of the human proteome [1,2]. Solute carriers (SLCs) constitute the second largest family of TM proteins [3]. There are 51 SLC classes, according to sequence similarity and functional properties, containing at least 386 human SLCs [3,4]. Three of the largest SLC families, SLC30, SLC35 and SLC39, comprising at least 10, 23, and 14 human proteins, respectively, contain protein domains that are members of the drug/metabolite transporter ("DMT") clan CL0184 in Pfam 24.0 [5]. A recent study presented evidence that the DMT-containing proteins are relatively dissimilar from other SLCs, and were present before the divergence of Bilateria [6].The DMT
%K SLC30
%K SLC35
%K SLC39
%K drug/metabolite transporters
%K nucleotide sugar transporters
%K EamA
%K EmrE
%K multi drug resistance protein
%K dual-topology proteins
%K transmembrane helix
%U http://www.biomedcentral.com/1471-2148/11/123