Yang X, Hubbard E J, Carlson M
Department of Genetics and Development, College of Physicians and Surgeons, Columbia University, New York, NY 10032.
Science. 1992 Jul 31;257(5070):680-2. doi: 10.1126/science.1496382.
A genetic method, the two-hybrid system, was used to identify four genes encoding proteins that interact with the SNF1 protein kinase from yeast. One of the genes, SIP1, was independently isolated as a multicopy suppressor of defects caused by reduced SNF1 kinase activity, and genetic evidence supports its function in the SNF1 pathway. The SIP1 protein co-immunoprecipitated with SNF1 and was phosphorylated in vitro. Thus, the two-hybrid system, which is applicable to any cloned gene, can be used to detect physical interactions between protein kinases and functionally related substrate proteins.