High impact information on RPI1

• We present evidence that the down-regulatory effect of RPI1 requires the presence of one of the two Ras GTPase activators, IRA1 and IRA2 [1].
• In particular, the RPI1 gene, a repressor of the ras-cAMP pathway, was found to be downregulated by Yap1p during the early phase of growth, but upregulated in the stationary phase or after oxidative stress [2].
• We isolated RPI1 as a high-copy-number suppressor of the cell lysis defect associated with a null mutation in the MPK1 gene, which encodes the mitogen-activated protein kinase of the cell wall integrity-signaling pathway [3].
• The RPI1 gene of Saccharomyces cerevisiae was identified initially as a dosage suppressor of the heat shock sensitivity associated with overexpression of RAS2 (J. Kim and S. Powers, Mol. Cell. Biol. 11:3894-3904, 1991) [3].
• Finally, we propose that inappropriate expression of RPI1 during log phase growth drives fortification of the cell wall and that this behavior is responsible for suppression of the mpkl cell lysis defect [3].

Associations of RPI1 with chemical compounds

• In contrast to the previous report, we found that RPI1 overexpression suppresses defects associated with mutational hyperactivation of the Ras/cAMP pathway at all points including constitutive mutations in the cAMP-dependent protein kinase [3].

References