G protein-cAMP signaling pathway mediated by PGA3 plays different roles in regulating the expressions of amylases and cellulases in Penicillium decumbens.
Heterotrimeric G proteins (G proteins) have been extensively investigated for their regulatory functions in morphogenesis and development in filamentous fungi. In addition, G proteins were also shown to be involved in the regulation of cellulase expression in some fungi. Here, we report the different regulatory effects of PGA3, a group III G protein α subunit, on the expressions of amylases and cellulases in Penicillium decumbens. Deletion of pga3 resulted in impaired amylase production and significantly decreased transcription of the major amylase gene amy15A. Supplementation of exogenous cAMP or its analog dibutyryl-cAMP restored amylase production in Δpga3 strain, suggesting an essential role of PGA3 in amylase synthesis via controlling cAMP level. On the other hand, the transcription of major cellulase gene cel7A-2 increased, nevertheless cellulase activity in the medium was not affected, in Δpga3. The above regulatory effects of PGA3 are carbon source-independent, and are achieved, at least, by cAMP-mediated regulation of the expression level of transcription factor AmyR. The functions of PGA3 revealed by gene deletion were partially supported by the analysis of the mutant carrying dominantly-activated PGA3. The results provided new insights into the understanding of the physiological functions of G protein-cAMP pathway in filamentous fungi.
State Key Laboratory of Microbial Technology, School of Life Science, Shandong University, Shan Da Nan Road 27, Jinan, Shandong 250100, PR China.
Yibo
Y
Hu
Guodong
G
Liu
Zhonghai
Z
Li
Yuqi
Y
Qin
Yinbo
Y
Qu
Xin
X
Song
D000681:Amylases / Q000235:genetics* / Q000378:metabolism; D044602:Cellulases / Q000235:genetics* / Q000378:metabolism; D000242:Cyclic AMP / Q000378:metabolism*; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D044385:GTP-Binding Protein alpha Subunits / Q000235:genetics / Q000378:metabolism*; D017353:Gene Deletion; D015971:Gene Expression Regulation, Enzymologic; D015966:Gene Expression Regulation, Fungal; D010407:Penicillium / Q000201:enzymology* / Q000235:genetics; D015398:Signal Transduction
D005656:Fungal Proteins; D044385:GTP-Binding Protein alpha Subunits; D000242:Cyclic AMP; D000681:Amylases; D044602:Cellulases
Amylase; Cellulase; G protein; Penicillium decumbens; cAMP