Sodium/solute symporter
IPR001734
Definition
Sodium/substrate symport (or co-transport) is a widespread mechanism of solute transport across cytoplasmic membranes of pro-and eukaryotic cells. Thereby the energy stored in an inwardly directed electrochemical sodium gradient (sodium motive force, SMF) is used to drive solute accumulation against a concentration gradient. The SMF is generated by primary sodium pumps (e.g. sodium/potassium ATPases, sodium translocating respiratory chain complexes) or via the action of sodium/proton antiporters. Sodium/substrate transporters are grouped in different families based on sequence similarities [[cite:PMID:1965458], [cite:PMID:8031825]]. One of these families, known as the sodium:solute symporter family (SSSF), contains over a hundred members of pro-and eukaryotic origin PMID:12354616. The average hydropathy plot for SSSF proteins predicts 11 to 15 putative transmembrane domains (TMs) in α-helical conformation. A secondary structure model of PutP from Escherichia coli suggests the protein contains 13 TMs with the N terminus located on the periplasmic side of the membrane and the C terminus facing the cytoplasm. The results support the idea of a common topological motif for members of the SSSF. Transporters with a C-terminal extension are proposed to have an additional 14th TM.
12 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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