cAMP-dependent protein kinase (PKA) plays a crucial role in the regulation of metabolic pathways by means of enzyme phosphorylation. PKA is one of the essential mediators of the cAMP signalling pathway. We have recently isolated the gene (pkaR) encoding the regulatory subunit of cAMP-dependent protein kinase (PKAR) from the industrially important fungus Aspergillus niger. The pkaR has an open reading frame of 1233 bp and encodes a polypeptide of 411 amino acids with calculated molecular mass of 44527 Da which corresponds to the Mr determined by SDS-PAGE (Legisa & Bencina, 1994, FEMS Microbiol Lett 118, 327-334). An intron was detected upstream of start codon. Its length is 700 bp. The deduced amino acid sequence of PKAR of A. niger shows extensive homology with PKAR isolated from other eukaryotes. The protein contains two putative cAMP binding sites and putative PKA phosphorylation site. The cloned pkaR and cloned pkaR and pkaC (catalytic subunit) (Bencina et al. 1997, Microbiology 143, 1211-1220) were used for transformation of A.niger. Transformants overexpressing pkaR and transformants overexpressing pkaR and pkaC are phenotypically similar to wild type strain. An A. niger strain with disrupted pkaR gene was isolated as well which was confirmed by Southern and Northern analysis. The pkaR disruptant strain was phenotipically different from wild type with respect to sporulation that was abolished.
Fungal Genet. Newsl. 46 (Supl):
Full conference title:
Fungal Genetics Conference 20th
- Fungal Genetics Conference 20th (1999)