Yeast cdc35 mutants are defective in adenylate cyclase and are allelic with cyr1 mutants while CAS1, a new gene, is involved in the regulation of adenylate cyclase.

Abstract

Newly isolated temperature‐sensitive cdc35 mutants of Saccharomyces cerevisiae have been characterized. They show the morphology, growth and conjugation characteristics typical of class‐A or class‐II start mutants. The cdc35 mutation induces a significant decrease of the intracellular cAMP level and produces a thermolabile adenylate cyclase. By classical genetic criteria the CDC35 gene is identical with the structural gene of adenylate cyclase, CYR1. The results of the mutant selection, the kinetics of macromolecule accumulation and the cell‐density change of cdc35 mutants at the restrictive temperature, indicate that CDC35 function may not be cell cycle‐specific. A new mutation, cas1, was isolated and partially characterized. It mediates the suppression by external cAMP of the unlinked cdc35 mutation. It causes a slight increase of the intracellular cAMP level and has strong effects on the adenylate cyclase activities, especially on the Mg2+ dependent activity. The data suggest that the CAS1 protein is a controlling element of adenylated cyclase. The CAS1 locus is different from the RAS1 and RAS2 loci.

Cyclic AMP controls the plasma membrane H+‐ATPase activity from Saccharomyces cerevisiae

“…Here, we show that thermosensitive cdc35 and cdc25 mutations, which at the restrictive temperature decrease the level of intracellular CAMP [12,13] of Saccharomyces cerevisiae, also decrease the plasma membrane H+-ATPase activity. In contrast, mitochondrial ATPase activity is increased under conditions that reduce the level of CAMP.…”

“…Within 2 h after shifting from the permissive temperature of 26"C, to the restrictive temperature of 36°C the intracellular content of CAMP decreased from 4.5 to 1.8 pmol/mg protein in the cdc35-10 mutant. In contrast, the CAMP content of the parental strain increased from 4 to 8 pmol/mg protein after a similar temperature shift [12]. Fig.lA,B shows the modification of plasma membrane and mitochondrial ATPase activities measured, respectively, at pH 6.0 and 9.0, in crude membranes from the wild-type e1278b and the mutant cdc35-10 after a shift from 26 to 36°C.…”

“…In contrast, mitochondrial ATPase activity is increased under conditions that reduce the level of CAMP. These effects are reversed by external CAMP when cdc35 and cdc25 are associated with casl, a mutation that mediates the suppression of the cdc35 and cdc25 phenotypes by external CAMP [12,13]. [12].…”

“…These effects are reversed by external CAMP when cdc35 and cdc25 are associated with casl, a mutation that mediates the suppression of the cdc35 and cdc25 phenotypes by external CAMP [12,13]. [12]. Strains were grown under aeration at 26°C on YEPD medium containing 1% yeast extract, 1% bactopeptone and 5.8% glucose.…”

Decrease in glycolytic flux in Saccharomyces cerevisiae cdc35-1 cells at restrictive temperature correlates with a decrease in glucose transport

“…Instead of a decrease, the intracellular cAMP levels were found to increase after a temperature shift, an effect that is usually observed for wild-type cells (Boutelet et al, 1985;Camonis e t al., 1986;Oehlen e t al., 1993). At restrictive temperature, the in viuo catalytic activity of adenylate cyclase from cdc35-1 cells may therefore be similar to that of wild-type cells.…”