Electrophoretic detection of multiple protein kinases in the entomopathogenic fungus Metarhizium anisopliae

Abstract

Multiple membrane bound protein kinases were detected following electrophoresis of a membrane preparation from Metarhizium anisopliae on sodium dodecyl sulfate-polyacrylamide gels. After renaturation, polypeptides in the gel were incubated with [γ-32P]ATP for phosphorylation of the kinases themselves or of histones or casein included in the gel. Eight radioactive bands were detected in ungerminated conidia, a 40 kDa band predominated. Sixteen bands (Mr range 28–72 kDa) were detected in both a crude extract and membrane fraction from mycelia. All of the bands were intensified when casein was included in the gel; four bands including the major 40-kDa band were intensified with mixed histones. The same bands were detected when the phosphorylation was carried out with or without Ca2+, calmodulin, EGTA, cyclic AMP, spermine or heparin. Most of the phosphorylating enzymes fit the general descriptions of casein kinases.