In prokaryotes, the heat shock response is characterized by the induction of several proteins including DnaJ, DnaK, GroEL and GroES. DnaK is a member of the HSP70 family, and like other members, exhibits ATPase activity which facilitates the release of bound proteins and disaggregation of protein complexes within the cell. Members of this protein group serve as molecular chaperones. Levels of DnaJ and DnaK are closely linked and, in E. coli, are constituents of a single operon. DnaJ regulates DnaK in several different systems. Relative to DnaK, the level of DnaJ synthesis is quite low. Studies have shown that DnaJ and DnaK, together with GrpE, cooperatively interact with firefly luciferase as it unfolds during thermal denaturation allowing renaturation of the protein upon return to normal temperatures. Also, DnaK together with DnaJ stimulates the binding of RepA initiator protein to the origin of P1 phage in vitro.
CPR3; DNAJA2; DNJ3; Escherichia coli; HDJ-2