Open AccessA putative role for calmodulin in the activation of Neurospora crassa chitin synthase
Author(s) -
Suresh K,
Subramanyam C
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb10355.x
Subject(s) - calmodulin , trifluoperazine , biochemistry , neurospora crassa , biology , chitin synthase , chitin , atp synthase , enzyme , mutant , chitosan , gene
The possible role of calmodulin in cell wall formation and chitin synthesis was studied in Neurospora crassa by examining the effects of anti‐calmodulin agents on protoplast regeneration and possible associations between chitin synthase and calmodulin related proteins in microsomal isolates. Protoplast regeneration was inhibited by trifluoperazine (>20 μM), an anti‐calmodulin agent. Chitin synthase activity in microsomes was associated with that of calmodulin‐dependent protein kinase and inhibited by trifluoperazine (100 μM). In vitro activity of chitin synthase was enhanced upon inclusion of calmodulin (300 ng) in the assay mix, 63% over and above the stimulation brought about by trypsin, an activator of the enzyme. Autoradiography studies on microsomal proteins revealed calmodulin‐dependent phosphorylation of two microsomal calmodulin‐binding proteins (106 and 89 kDa). The results indicate that calmodulin‐mediated phosphorylation of specific microsomal proteins may be important in the in vivo activation of chitin synthase.