Rax1, a protein required for the establishment of the bipolar budding pattern in yeast.
In Saccharomyces cerevisiae, cell type determines two distinct spatial budding patterns. Haploid cells exhibit an axial pattern, whereas diploid cells exhibit a bipolar pattern. Axl1, a member of the insulin-degrading enzyme (IDE) family, is the key morphological determinant for the haploid axial pattern. Here we identified a novel gene, RAX1, specifically required for the bipolar budding pattern. Loss of RAX1 alters the bipolar pattern of axl1 haploids resulting in reversion to the axial pattern, and also alters the bipolar patterns of bud3 and bud4 haploids. However, bud10 rax1 haploids exhibit a random budding pattern, suggesting Bud10 acts as the key proximal landmark in axial budding. Rax1 is required for the localization of Bud8, the distal bipolar budding landmark. Interestingly, Rax1 contains a C-terminal domain possessing some similarity to insulin-related peptides. Our results suggest that Rax1 is necessary for the establishment of the bipolar budding landmark.
National Institute of Advanced Industrial Science and Technology, Tsukuba Central 6-4, 1-1 Higashi, Tsukuba 305-8566, Japan. a-fujita@aist.go.jp
Atsushi
A
Fujita
Matthew
M
Lord
Takatoshi
T
Hiroko
Fumika
F
Hiroko
Tracy
T
Chen
Chitoshi
C
Oka
Yoshio
Y
Misumi
John
J
Chant
D000595:Amino Acid Sequence; D002455:Cell Division / Q000235:genetics; D004171:Diploidy; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D008565:Membrane Proteins; D008666:Metalloendopeptidases; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D009154:Mutation; D011956:Receptors, Cell Surface / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000254:growth & development; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic / Q000235:genetics
C104374:BUD10 protein, S cerevisiae; C419588:BUD8 protein, S cerevisiae; C419589:BUD9 protein, S cerevisiae; D008164:Luminescent Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; C483715:RAX1 protein, S cerevisiae; D011956:Receptors, Cell Surface; D011993:Recombinant Fusion Proteins; D029701:Saccharomyces cerevisiae Proteins; D049452:Green Fluorescent Proteins; C090850:AXL1 protein, S cerevisiae; D008666:Metalloendopeptidases