Functional homology of protein kinases required for sexual differentiation in Schizosaccharomyces pombe and Saccharomyces cerevisiae suggests a … (original) (raw)

1993, Molecular biology of …

We present genetic evidence that three presumptive protein kinases of Schizosaccharomyces pombe, byr2, byrl, and spkl that are structurally related to protein kinases of Saccharomyces cerevisiae, STE11, STE7, and FUS3, respectively, are also functionally related. In some cases, introduction of the heterologous protein kinase into a mutant was sufficient for complementation. In other cases (as in a stellmutant of S. cerevisiae), expression of two S. pombe protein kinases (byr2 and byrl) was required to observe complementation, suggesting that byr2 and byrl act cooperatively. Complementation in S. pombe mutants is observed as restoration of sporulation and conjugation and in S. cerevisiae as restoration of conjugation, pheromone-induced cell cycle arrest, and pheromone-induced transcription of the FUSI gene. We also show that the S. pombe kinases bear a similar relationship to the mating pheromone receptor apparatus as do their S. cerevisiae counterparts. Our results indicate that pheromone-induced signal transduction employs a conserved set of kinases in these two evolutionarily distant yeasts despite an apparently significant difference in function of the heterotrimeric G proteins. We suggest that the STE11/byr2, STE7/byrl, and FUS3/spkl kinases comprise a signal transduction module that may be conserved in higher eukaryotes. Consistent with this hypothesis, we show that a mammalian mitogenactivated protein (MAP) kinase, ERK2, can partially replace spkl function in S. pombe. Laboratory collection AN40-5A MATa his4-519 ura3-52 leu2 trpl ste7A2 stellAl This study AN42-2A MATa his4-519 ura3-52 leu2 trpl fus3::URA3 kssl::URA3 This study AN37-4C-S MATa ura3-52 leu2 trpl ade2 metl HMLa HMRa barl-i Laboratory collection AN1015 MATa ura3-52 leu2 trpl ade2 metl HMLa HMRa barl-I fus3::URA3 This study AN1016 MATa his4-519 ura3-52 leu2 trpl stellAl FUSI::lacZ (LEU2) This study 5815-7-1 MATca ura3 his3 hopl-1