Sugito K, Yamane M, Hattori H, Hayashi Y, Tohnai I, Ueda M, Tsuchida N, Ohtsuka K
Department of Oral Surgery, Nagoya University School of Medicine, Japan.
FEBS Lett. 1995 Jan 23;358(2):161-4. doi: 10.1016/0014-5793(94)01417-y.
We have recently identified a novel 40-kDa heatshock protein hsp40 as a mammalian homologue of bacterial DnaJ protein. Here we demonstrate the physical interaction between hsp70 (DnaK homologue) and hsp40 in human cells as determined by immunoprecipitation methods. Co-immunoprecipitation of hsp70 with hsp40 was dependent on the presence of ATP or unfolded protein (reduced carboxymethylated alpha-lactalbumin). A mutant type of tumor suppressor gene product, mtp53, was co-immunoprecipitated not only with hsp70 but also with hsp40. These results suggest the existence of a hsp70(DnaK)/hsp40(DnaJ) chaperone system in mammalian cells.
