Novel Ca2+/calmodulin-dependent protein kinase expressed in actively growing mycelia of the basidiomycetous mushroom Coprinus cinereus.
We isolated cDNA clones for novel protein kinases by expression screening of a cDNA library from the basidiomycetous mushroom Coprinus cinereus. One of the isolated clones was found to encode a calmodulin (CaM)-binding protein consisting of 488 amino acid residues with a predicted molecular weight of 53,906, which we designated CoPK12. The amino acid sequence of the catalytic domain of CoPK12 showed 46% identity with those of rat Ca2+/CaM-dependent protein kinase (CaMK) I and CaMKIV. However, a striking difference between these kinases is that the critical Thr residue in the activating phosphorylation site of CaMKI/IV is replaced by a Glu residue at the identical position in CoPK12. As predicted from its primary sequence, CoPK12 was found to behave like an activated form of CaMKI phosphorylated by an upstream CaMK kinase, indicating that CoPK12 is a unique CaMK with different properties from those of the well-characterized CaMKI, II, and IV. CoPK12 was abundantly expressed in actively growing mycelia and phosphorylated various proteins, including endogenous substrates, in the presence of Ca2+/CaM. Treatment of mycelia of C. cinereus with KN-93, which was found to inhibit CoPK12, resulted in a significant reduction in growth rate of mycelia. These results suggest that CoPK12 is a new type of multifunctional CaMK expressed in C. cinereus, and that it may play an important role in the mycelial growth.
Kaneko
Keisuke
K
Department of Life Sciences, Faculty of Agriculture, Kagawa University, Ikenobe 2393, Miki-cho, Kagawa 761-0795, Japan.
Yamada
Yusuke
Y
Sueyoshi
Noriyuki
N
Watanabe
Akira
A
Asada
Yasuhiko
Y
Kameshita
Isamu
I
D000595:Amino Acid Sequence; D000818:Animals; D001596:Benzylamines / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D002384:Catalysis; D003302:Coprinus / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D005656:Fungal Proteins / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification; D008969:Molecular Sequence Data; D025282:Mycelium / Q000187:drug effects / Q000201:enzymology* / Q000254:growth & development; D010766:Phosphorylation; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051381:Rats; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification; D017386:Sequence Homology, Amino Acid; D013449:Sulfonamides / Q000494:pharmacology; D000096926:Benzenesulfonamides
D001596:Benzylamines; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D005656:Fungal Proteins; D047428:Protein Kinase Inhibitors; D011994:Recombinant Proteins; D013449:Sulfonamides; C072105:KN 93; D000096926:Benzenesulfonamides