In order to determine a cellular localization of protein kinase StkP we prepared its epitope-labelled form expressed in S. pneumoniae. The full-length form of StkP was detected with monoclonal antibody in the membrane fraction. In vitro autophosphorylation assays confirmed this finding and phosphorylated product of corresponding mass was detected in the membranes. These results clearly showed that StkP is a membrane-associated protein.
Petra Pallová (Thu,) studied this question.