Multiple functions of the vacuolar sorting protein Ccz1p in Saccharomyces cerevisiae.
Marta Hoffman-Sommer, Aleksandra Jaszcza, Joanna Rytka, Róza Kucharczyk
Department of Genetics, IBB PAS, Pawinskiego 5a, Warsaw, 02-106, Poland
The CCZ1 ( YBR131w ) gene encodes a protein required for fusion of various transport intermediates with the vacuole. Ccz1p, in a complex with Mon1p, is a close partner of Ypt7p in the processes of fusion of endosomes to vacuoles and homotypic vacuole fusion. Apart from the interactions of the CCZ1 gene with MON1, we show the specificity of an interaction between the CCZ1 and ARL1 genes. ARL1 encodes a GTPase associated with the Golgi complex, indicating a possible role of Ccz1p in the regulation of membrane traffic/fusion at the stage of the Golgi compartment. We also show a synthetic interaction between CCZ1 and PEP12, as well as between CCZ1 and SYN8 - two genes encoding proteins of the SNARE family, related to mammalian syntaxins. Our results indicate a role of Ccz1p in SNARE-mediated membrane traffic from the trans-Golgi network to the prevacuolar compartment.