Intracellular transport of a heterologous membrane protein, the human transferrin receptor, in Saccharomyces cerevisiae.
We have analyzed the intracellular behavior of the human transferrin receptor (TfR) in Saccharomyces cerevisiae. The major part of the heterologously expressed TfR, which has previously been used as a model for heterologous expression of membrane proteins in yeast, is localized in the endoplasmic reticulum (ER) membranes; a minor fraction is present in the plasma membrane (PM). The stability of the TfR depends on vacuolar proteases, implying that it is degraded in the vacuolar compartment. Degradation is further dependent on favorable transport conditions to this compartment. The main bottleneck of transport seems to be the transition from the ER to the PM. The chaperone Cne1p, which is involved in quality control in the ER, plays a role in regulating the amount of heterologous TfR, as deletion of CNE1 leads to significant accumulation of the protein. This is the first demonstration of the involvement of CNE1 in regulating the level of heterologous membrane proteins.
Institute for Biotechnology, Department of Microbiology and Genetics, Berlin University of Technology, Gustav-Meyer-Allee 25, 13355, Berlin, Germany.
Bianka
B
Prinz
Ulf
U
Stahl
Christine
C
Lang
D001673:Biodegradation, Environmental; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000378:metabolism; D018832:Molecular Chaperones / Q000235:genetics; D021381:Protein Transport; D011990:Receptors, Transferrin / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism*; D014617:Vacuoles / Q000378:metabolism
D018832:Molecular Chaperones; D011990:Receptors, Transferrin