- Sensitivity to Hsp90-targeting drugs can arise with mutation to the Hsp90 chaperone, cochaperones and plasma membrane ATP binding cassette transporters of yeast. Piper, P.W., Millson, S.H., Mollapour, M., Panaretou, B., Siligardi, G., Pearl, L.H., Prodromou, C. Eur. J. Biochem. (2003)