14-3-3 proteins: potential roles in vesicular transport and Ras signaling in Saccharomyces cerevisiae.
Deletion of the clathrin heavy-chain gene, CHC1, in the budding yeast Saccharomyces cerevisiae results in growth, morphological, and membrane trafficking defects, and in some strains chc1-delta is lethal. A previous study identified five genes which, in multicopy, rescue inviable strains of Chc- yeast. Now we report that one of the suppressor loci, BMH2/SCD3, encodes a protein of the 14-3-3 family. The 14-3-3 proteins are abundant acidic proteins of approximately 30 kDa with numerous isoforms and a diverse array of reported functions. The Bmh2 protein is > 70% identical to the mammalian epsilon-isoform and > 90% identical to a previously reported yeast 14-3-3 protein encoded by BMH1. Single deletions of BMH1 or BMH2 have no discernable phenotypes, but deletion of both BMH1 and BMH2 is lethal. High-copy BMH1 also rescues inviable strains of Chc- yeast, although not as well as BMH2. In addition, the slow growth of viable strains of Chc- yeast is further impaired when combined with single bmh mutations, often resulting in lethality. Overexpression of BMH genes also partially suppresses the temperature sensitivity of the cdc25-1 mutant, and high-copy TPK1, encoding a cAMP-dependent protein kinase, restores Bmh- yeast to viability. High-copy TPK1 did not rescue Chc- yeast. These genetic interactions suggest that budding-yeast 14-3-3 proteins are multifunctional and may play a role in both vesicular transport and Ras signaling pathways.
Gelperin
D
D
Department of Molecular Biology and Microbiology, Case Western Reserve University, Cleveland, OH 44106-4960, USA.
Weigle
J
J
Nelson
K
K
Roseboom
P
P
Irie
K
K
Matsumoto
K
K
Lemmon
S
S
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D001692:Biological Transport / Q000235:genetics; D002966:Clathrin / Q000172:deficiency / Q000235:genetics; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D018628:Gene Dosage; D015966:Gene Expression Regulation, Fungal; D007425:Intracellular Membranes / Q000378:metabolism*; D008969:Molecular Sequence Data; D016296:Mutagenesis; D011506:Proteins / Q000235:genetics; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism / Q000528:radiation effects; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013489:Suppression, Genetic; D014446:Tyrosine 3-Monooxygenase; D014466:Ultraviolet Rays; D018631:ras Proteins / Q000378:metabolism*
D048948:14-3-3 Proteins; C075852:BMH1 protein, S cerevisiae; C097164:BMH2 protein, S cerevisiae; D002966:Clathrin; D005656:Fungal Proteins; D011506:Proteins; D029701:Saccharomyces cerevisiae Proteins; D014446:Tyrosine 3-Monooxygenase; D018631:ras Proteins