The common 90-kd protein component of non-transformed '8S' steroid receptors is a heat-shock protein.

AUTOR(ES)

Catelli, M G

RESUMO

Non-transformed steroid receptors have an approximately 8S sedimentation coefficient that corresponds to an oligomeric structure of 250-300 kd which includes a non-hormone binding 90-kd protein. A monoclonal antibody BF4 raised against the purified, molybdate-stabilized, 8S progesterone receptor (8S-PR) from chick oviduct, recognizes 8S forms of all steroid hormone receptors. BF4 was found specific for a 90-kd protein present in great abundance in all chicken tissues, including that present in 8S-forms of steroid receptors. Here, using immunological and biochemical techniques, we demonstrate that this ubiquitous BF4-positive 90-kd protein is in fact the chicken 90 kd heat-shock protein (hsp 90): it increased in heat-shocked chick embryo fibroblasts, and displayed identical migration in two-dimensional gel electrophoresis and the same V8 peptide map as the already described hsp 90. We discuss the possibility that the interaction between hsp 90 and steroid hormone-binding subunits may play a role in keeping the receptor in an inactive form.

Documentos Relacionados

• lon gene product of Escherichia coli is a heat-shock protein.
• A 75 kd merozoite surface protein of Plasmodium falciparum which is related to the 70 kd heat-shock proteins.
• A human homologue of the Escherichia coli DnaJ heat-shock protein.
• Herpes simplex virus infection causes the accumulation of a heat-shock protein.
• Autoantibodies to the heat-shock protein hsp90 in systemic lupus erythematosus.