9.B.82 The Endoplasmic Reticulum Retrieval Protein1 (Putative Heavy Metal Transporter) (Rer1) Family
Mutations in the gene encoding the 4 TMS (2 + 2) Rer1 protein in S. cerevisiae (of about 190 aas as are most of its homologues) can be complemented by human NRAMP1 (TC# 2.A.55.2.3), suggesting that it might be a heavy metal efflux pump (Techau et al., 2007). It has homologues in many fungi, animals, plants and other eukaryotes, almost all of about 190 aas. Single oraganisms can have multiple paralogues. Downregulation of Rer1 leads to increased surface localization of Pen2 (a component of the γ-secretase complex), whereas overproduction of Rer1 stabilizes unassembled Pen2. Rer1 is the first identified interaction partner of mammalian transmembrane-based retention/retrieval signals (Kaether et al. 2007).