title: PKA from Mucor circinelloides: model to study the role of linker I in the interaction between R and C subunits.
abstract: Protein kinase A from the fungus Mucor circinelloides shows high affinity interaction between regulatory (R) and catalytic (C) subunits. Its R subunit shows a differential presence of several acidic residues in linker I region, in the amino terminus. Mutants R1, lacking the N-terminal region, and R2, lacking the acidic cluster, were used to analyze its effect on the interaction with the C subunit, assessed through inhibition of catalytic activity and cAMP activation of reconstituted holoenzyme. A similar decrease in the interaction was obtained when using R1 and R2 with the homologous C subunit; however when using heterologous bovine C, only R1 had a decreased interaction. The results show the general importance of linker I region in the R-C interaction in protein kinases A and point to the importance of the acidic cluster present in the N-terminus of M. circinelloides R subunit in the high affinity interaction between R and C in this holoenzyme.
authors.affiliation: Departamento de Química Biológica, Facultad de Ciencias Exactas y, Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón 2, 1428 Buenos Aires, Argentina.
authors.forename: Josefina
authors.initials: J
authors.lastname: Ocampo
authors.forename: Silvia
authors.initials: S
authors.lastname: Moreno
authors.forename: Silvia
authors.initials: S
authors.lastname: Rossi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D020134:Catalytic Domain; D002417:Cattle; D000242:Cyclic AMP / Q000378:metabolism; D017868:Cyclic AMP-Dependent Protein Kinases / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D020869:Gene Expression Profiling; D007700:Kinetics; D008969:Molecular Sequence Data; D009089:Mucor / Q000201:enzymology*; D016296:Mutagenesis; D009154:Mutation; D010766:Phosphorylation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D017386:Sequence Homology, Amino Acid
chemical_list: D000242:Cyclic AMP; D017868:Cyclic AMP-Dependent Protein Kinases