SHR3: a novel component of the secretory pathway specifically required for localization of amino acid permeases in yeast.
Mutations in SHR3 block amino acid uptake into yeast by reducing the levels of multiple amino acid permeases within the plasma membrane. SHR3 is a novel integral membrane protein component of the endoplasmic reticulum (ER). shr3 null mutants specifically accumulate amino acid permeases in the ER; other plasma membrane proteins, secretory proteins, and vacuolar proteins are processed and targeted correctly. Our findings suggest that SHR3 interacts with a structural domain shared by amino acid permeases, an interaction required for permease-specific processing and transport from the ER. Even in the presence of excess amino acids, shr3 mutants exhibit starvation responses. shr3 mutants constitutively express elevated levels of GCN4, and mutant shr3/shr3 diploids undergo dimorphic transitions that result in filamentous growth at enhanced frequencies.
Ljungdahl
P O
PO
Whitehead Institute for Biomedical Research, Cambridge, Massachusetts 02142.
Gimeno
C J
CJ
Styles
C A
CA
Fink
G R
GR
D000595:Amino Acid Sequence; D026905:Amino Acid Transport Systems; D001483:Base Sequence; D001692:Biological Transport; D002874:Chromosome Mapping; D004721:Endoplasmic Reticulum / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D026901:Membrane Transport Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D016366:Open Reading Frames; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins
D026905:Amino Acid Transport Systems; D008565:Membrane Proteins; D026901:Membrane Transport Proteins; C077883:SHR3 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins