Vol. 13, Issue 1, 40-51, January 2002

IN02, A Positive Regulator of Lipid Biosynthesis, Is Essential for the Formation of Inducible Membranes in Yeast

Laura Block-Alper,^* Paul Webster, Xianghong Zhou,^§ Lubica Supeková, Wing Hung Wong,^§ Peter G. Schultz, and David I. Meyer^*¶

 ^*Department of Biological Chemistry, University of California Los Angeles School of Medicine, Los Angeles, California 90024;  Ahmanson Center for Advanced EM & Imaging, House Ear Institute, Los Angeles, California 90057;  Institute for Pure and Applied Mathematics, University of California at Los Angeles, Los Angeles, California 90095; and  Department of Chemistry, The Scripps Research Institute, La Jolla, California 92037

Expression of the 180-kDa canine ribosome receptor in Saccharomyces cerevisiae leads to the accumulation of ER-like membranes. Gene expression patterns in strains expressing various forms of p180, each of which gives rise to unique membrane morphologies, were surveyed by microarray analysis. Several genes whose products regulate phospholipid biosynthesis were determined by Northern blotting to be differentially expressed in all strains that undergo membrane proliferation. Of these, the INO2 gene product was found to be essential for formation of p180-inducible membranes. Expression of p180 in ino2 cells failed to give rise to the p180-induced membrane proliferation seen in wild-type cells, whereas p180 expression in ino4 cells gave rise to membranes indistinguishable from wild type. Thus, Ino2p is required for the formation of p180-induced membranes and, in this case, appears to be functional in the absence of its putative binding partner, Ino4p.