Scallop DMT functions as a Ca2+ transporter

We identified a DMT (divalent metal transporter) homologous protein that functions as a Ca2+ transporter. Scallop DMT cDNA encodes a 539‐amino‐acid protein with 12 putative membrane‐spanning domains and has a consensus transport motif in the fourth extracellular loop. Since its mRNA is significantly expressed in the gill and intestine, it is assumed that scallop DMT transports Ca2+ from seawater by the gill and from food by the intestine. Scallop DMT lacks the iron‐responsive element commonly found in iron‐regulatory proteins, suggesting that it is free of the post‐transcriptional regulation from intracellular Fe2+ concentration. Scallop DMT distinctly functions as a Ca2+ transporter unlike other DMTs, however, it also transports Fe2+ and Cd2+ similar to them.