title: Putative calmodulin-binding domains in aflatoxin biosynthesis-regulatory proteins.
abstract: 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.
authors.affiliation: Department of Biotechnology, The University of Tokyo, 1-1-1 Yayoi, Tokyo 113-8657, Japan. ajuvvadi@mail.ecc.u-tokyo.ac.jp
authors.forename: Praveen Rao
authors.initials: PR
authors.lastname: Juvvadi
authors.forename: Subramanyam
authors.initials: S
authors.lastname: Chivukula
mesh_terms: 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
chemical_list: C113837:AFLR protein, Aspergillus; D000348:Aflatoxins; D002147:Calmodulin; D002148:Calmodulin-Binding Proteins; D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D014157:Transcription Factors; D014268:Trifluoperazine