Lesuisse E, Horion B, Labbe P, Hilger F
Laboratoire de Biochimie des Porphyrines, Université Paris, France.
Biochem J. 1991 Dec 1;280 ( Pt 2)(Pt 2):545-8. doi: 10.1042/bj2800545.
The plasma-membrane-bound ferrireductase activity of ras1 and ras2 mutants of Saccharomyces cerevisiae is not induced in response to iron limitation. This phenotype was suppressed by the bcy1 mutation in ras2 but not in ras1 mutants. The cellular haem content of ras-1-bearing strains decreased dramatically when cells were grown in semi-synthetic medium (low yeast extract content), which could account for their very low ferrireductase activity. The ferrireductase activity of cdc25 and cdc35 mutants dropped when the cells were shifted to a non-permissive temperature. This drop was prevented in the double mutant cdc35 sra5 by adding cyclic AMP to the growth medium. We propose that ferrireductase activity is under the control of a cyclic AMP-dependent protein phosphorylation.
酿酒酵母ras1和ras2突变体的质膜结合铁还原酶活性在铁限制条件下不会被诱导。ras2中的bcy1突变可抑制该表型，但ras1突变体中则不能。当细胞在半合成培养基（酵母提取物含量低）中生长时，携带ras-1的菌株细胞内的血红素含量会急剧下降，这可以解释其极低的铁还原酶活性。当细胞转移到非允许温度时，cdc25和cdc35突变体的铁还原酶活性下降。通过向生长培养基中添加环磷酸腺苷，可防止双突变体cdc35 sra5出现这种下降。我们认为铁还原酶活性受环磷酸腺苷依赖性蛋白磷酸化的控制。
