The HPV-16 E5 oncogene and bafilomycin A(1) influence cell motility

It is known that the proper function of the vacuolar H+-ATPase is inhibited by bafilomycin A(1). In transfected cells the E5 protein interacts with th e 16 kDa subunit of the vacuolar H+-ATPase. Thereby the pH gradient in endo cytic structures is impaired. The present study demonstrates for the first time that the inhibition of the vacuolar H+-ATPase in NIH3T3 cells with baf ilomycin A(1) or by transfection of cells with the HPV-16 E5 oncogene leads to a changed morphology and a reduced motility as shown by computer-assist ed video recordings and image analysis. Bafilomycin A(1) potentiates the ef fect of the E5 protein on cell motility and this cooperative effect indicat es that the E5 protein and bafilomycin A(1) either target the vacuolar H+-A TPase differently or that the E5 protein has additional targets in transfec ted cells. Our data therefore show that proper function of-the vacuolar H+- ATPase is needed for normal cell locomotion. (C) 1999 Elsevier Science B.V. All rights reserved.