The Ccz1 protein interacts with Ypt7 GTPase during fusion of multiple transport intermediates with the vacuole in S. cerevisiae.
Previously we have shown that the Saccharomyces cerevisiae CCZ1 (YBR131w) gene encodes a protein involved in protein trafficking. Deletion of this gene leads to fragmentation of the vacuole typical of the class B vps mutants. Genetic and biochemical data indicated that Ccz1p is required for fusion of various transport intermediates with the vacuole. Here we present data indicating that CCZ1 is a close partner of the YPT7 gene, which encodes Rab GTPase and is required for fusion of transport vesicles to vacuole and homotypic vacuole fusion. We isolated extragenic suppressors of CCZ1 deletion. All these suppressors belong to one complementation group and correspond to mutated alleles of the YPT7 gene. The mutated residues are located in two Ypt7p domains responsible for guanine binding. These data suggest that Ccz1p and Ypt7p interact physically. Coimmunoprecipitation experiments provide direct evidence that this indeed is the case. A possible mechanism of Ccz1p action is discussed.
Kucharczyk
R
R
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Pawinskiego 5A, 02-106 Warsaw, Poland.
Kierzek
A M
AM
Slonimski
P P
PP
Rytka
J
J
D000409:Alanine / Q000737:chemistry; D000483:Alleles; D000595:Amino Acid Sequence; D001224:Aspartic Acid / Q000737:chemistry; D001692:Biological Transport; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002352:Carrier Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D000697:Central Nervous System Stimulants / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D000939:Epitopes; D017353:Gene Deletion; D015723:Gene Library; D005816:Genetic Complementation Test; D006147:Guanine / Q000737:chemistry; D020662:Guanine Nucleotide Exchange Factors; D006388:Hemagglutinins / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D010641:Phenotype; D016133:Polymerase Chain Reaction; D011233:Precipitin Tests; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D014617:Vacuoles / Q000378:metabolism*; D033921:Vesicular Transport Proteins; D015032:Zinc / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000235:genetics* / Q000378:metabolism*
D002352:Carrier Proteins; C441960:Ccz1 protein, S cerevisiae; D000697:Central Nervous System Stimulants; D000939:Epitopes; D020662:Guanine Nucleotide Exchange Factors; D006388:Hemagglutinins; D029701:Saccharomyces cerevisiae Proteins; D033921:Vesicular Transport Proteins; D001224:Aspartic Acid; D002110:Caffeine; D006147:Guanine; D004247:DNA; C079005:YPT7 protein, S cerevisiae; D020691:rab GTP-Binding Proteins; D015032:Zinc; D000409:Alanine; D002118:Calcium