NITROGEN-SOURCE-INDUCED ACTIVATION OF NEUTRAL TREHALASE IN SCHIZOSACCHAROMYCES-POMBE AND PACHYSOLEN-TANNOPHILUS - ROLE OF CAMP AS 2ND-MESSENGER

Resting cells of the fission yeast Schizosaccharomyces pombe, suspende d in buffer with glucose. responded to the addition of asparagine by i ncreasing trehalase activity. This response was preceded by a peak in cAMP concentration. The addition of the nitrogen source to resting cel ls, devoid of the catalytic subunit of cAMP-dependent protein kinase, produced the transient increase in cAMP but did not promote any change in trehalase activity. In the budding yeast Pachysolen tannophilus, t he activation of trehalase by nitrogen source was also accompanied by a sharp peak in cAMP. These results suggest that in the two yeasts cAM P acts as a second messenger in the transduction of the nitrogen-sourc e-induced signal causing the activation of trehalase.