Expression of the 180-kD ribosome receptor induces membrane proliferation and increased secretory activity in yeast.
Expression of the canine 180-kD ribosome receptor (p180) in yeast cells resulted in a marked proliferation of intracellular membranes. The type of membranes observed varied with the expression of specific portions of p180. Rough membranes predominated when the ribosome binding domain of p180 was present, whereas expression constructs lacking this region resulted in smooth membranes. Northern analysis indicated that expression of the NH(2)-terminal 767 amino acids (DeltaCT), which include the ribosome binding domain, upregulated the transcription and translation of genes involved in exocytosis. The membranes that were proliferated were functional as these cells overcame a temperature-sensitive translocation defect. Most significantly, cells that overexpressed DeltaCT and proliferated rough endoplasmic reticulum exhibited severalfold higher levels of secretion of an ectopically expressed secretory protein. We conclude that p180 expression triggers a cascade of events leading to an increase in secretory potential akin to the terminal differentiation of mammalian secretory cells and tissues.
Becker
F
F
Department of Biological Chemistry and the Molecular Biology Institute, University of California, Los Angeles School of Medicine, Los Angeles, California 90024, USA.
Block-Alper
L
L
Nakamura
G
G
Harada
J
J
Wittrup
K D
KD
Meyer
D I
DI
D000818:Animals; D007611:Aprotinin / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D015415:Biomarkers / Q000032:analysis; D004285:Dogs; D004721:Endoplasmic Reticulum / Q000235:genetics / Q000378:metabolism / Q000648:ultrastructure; D005089:Exocytosis / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal; D005800:Genes, Fungal / Q000235:genetics; D006056:Golgi Apparatus / Q000378:metabolism / Q000648:ultrastructure; D007425:Intracellular Membranes / Q000378:metabolism* / Q000648:ultrastructure; D008970:Molecular Weight; D009154:Mutation; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000166:cytology* / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D013696:Temperature; D014170:Transformation, Genetic; D015854:Up-Regulation
D015415:Biomarkers; D005656:Fungal Proteins; D010446:Peptide Fragments; D018160:Receptors, Cytoplasmic and Nuclear; C065526:ribosome receptor; D007611:Aprotinin