Evolutionary gain of function for the ER membrane protein Sec62 from yeast to humans.
Because of similarity to their yeast orthologues, the two membrane proteins of the human endoplasmic reticulum (ER) Sec62 and Sec63 are expected to play a role in protein biogenesis in the ER. We characterized interactions between these two proteins as well as the putative interaction of Sec62 with ribosomes. These data provide further evidence for evolutionary conservation of Sec62/Sec63 interaction. In addition, they indicate that in the course of evolution Sec62 of vertebrates has gained an additional function, the ability to interact with the ribosomal tunnel exit and, therefore, to support cotranslational mechanisms such as protein transport into the ER. This view is supported by the observation that Sec62 is associated with ribosomes in human cells. Thus, the human Sec62/Sec63 complex and the human ER membrane protein ERj1 are similar in providing binding sites for BiP in the ER-lumen and binding sites for ribosomes in the cytosol. We propose that these two systems provide similar chaperone functions with respect to different precursor proteins.
Müller
Linda
L
Medical Biochemistry and Molecular Biology, Saarland University, Homburg, Germany.
de Escauriaza
Maria Diaz
MD
Lajoie
Patrick
P
Theis
Melanie
M
Jung
Martin
M
Müller
Anika
A
Burgard
Carsten
C
Greiner
Markus
M
Snapp
Erik L
EL
Dudek
Johanna
J
Zimmermann
Richard
R
D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D004331:Drosophila melanogaster; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004926:Escherichia coli / Q000378:metabolism; D019143:Evolution, Molecular; D006801:Humans; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020349:Surface Plasmon Resonance
D026901:Membrane Transport Proteins; C074213:SEC62 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins