An interaction between p21^ras and heat shock protein hsp60, a chaperonin

Ras proteins play a crucial role in the development of neoplasia and in signal transduction in normal cells. In a search for proteins interacting with p21^ras, we previously identified a protein of 60 kDa (p60) through use of a chemical cross-linker. Using information from partial amino acid sequencing of the purified protein, we isolated full-length cDNA clones encoding this 60-kDa protein. Nucleotide sequence analysis revealed that p60 is the murine heat shock protein hsp60, a chaperonin. Association of hsp60 with p21^ras appears physiological, as the amount of hsp60 complexed to p21^ras was similar even in cells over-expressing p21^ras, and reversing the order of cross-linking and lysis of the cells, which releases large amounts of hsp60 from mitochondria, did not alter the amount of hsp60 cross-linked to p21^ras.