Putative calmodulin-binding domains in aflatoxin biosynthesis-regulatory proteins.
The inhibition of aflatoxin production by trifluoperazine, an anticalmodulin (CaM) agent and the relevance of Ca(2+)/CaM-dependent phosphorylation and dephosphorylation during aflatoxin biosynthesis was previously reported. To identify proteins that may be regulated by CaM, an in silico analysis for putative CaM-binding domains (CaMBDs) in the aflatoxin-related proteins of Aspergillus parasiticus was performed using the CaM target database. Interestingly, the key regulators of aflatoxin biosynthesis such as AflR and AflJ contained predicted CaMBDs at their C-termini. Furthermore, potential phosphorylation sites for CaM-kinase II were present within these CaMBDs. In addition to other aflatoxin biosynthesis enzymes--such as Vbs, DmtA and OmtA, and the VeA protein (known to regulate the expression of AflJ and AflR)--also showed the presence of putative CaMBDs. Although the present report reaffirms earlier observations on CaM-mediated regulation of aflatoxin biosynthesis, it also opens new avenues for identifying the specific targets of CaM and elucidating the exact mechanism of initiation and regulation of aflatoxin biosynthesis.
Juvvadi
Praveen Rao
PR
Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Tokyo 113-8657, Japan. ajuvvadi@mail.ecc.u-tokyo.ac.jp
Chivukula
Subramanyam
S
D000348:Aflatoxins / Q000096:biosynthesis*; D020816:Amino Acid Motifs; D001230:Aspergillus / Q000737:chemistry*; D002147:Calmodulin / Q000037:antagonists & inhibitors / Q000378:metabolism*; D002148:Calmodulin-Binding Proteins / Q000737:chemistry* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000737:chemistry; D005656:Fungal Proteins / Q000737:chemistry; D010766:Phosphorylation; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000737:chemistry; D014268:Trifluoperazine / Q000494:pharmacology
C113837:AFLR protein, Aspergillus; D000348:Aflatoxins; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D014157:Transcription Factors; D014268:Trifluoperazine