A 60 kD heat-shock protein-like molecule interacts with the HIV transmembrane glycoprotein gp41

The heat-shock protein hsp60 is typically found in mitochondria. but, in sm aller amounts, also in the cell cytoplasm and associated with the cell memb rane. Since heat-shock proteins are known to interact with a variety of mol ecules and since purified HIV-1 particles were described to contain hsp60 m olecules, we tested the possibility that a previously described putative re ceptor for HIV transmembrane protein gp41 is identical to hsp60. The gp41-b inding human protein P62 was purified from H9 and Raji cell lysates by a gp 41-coupled affinity column. We could show crossreactivity of both polyclona l and monoclonal anti-hsp60 antibodies with the purified P62. In addition w e analyzed binding of P18, a soluble gp41 fragment harboring the extracellu lar domain (Env aa539-684), to recombinant hsp60. Hsp60 bound well to P18-c oated ELISA plates whereas HIV-1 surface protein gp120 induced no binding o f hsp60. Preincubation of hsp60 with gp41 abolished the binding. The possib le role of this molecule as a cofactor in the pathogenesis of HIV disease i s discussed. (C) 1999 Elsevier Science Ltd. All rights reserved.