A Mr 7 kDa protein is present in both plasma and nuclear membranes in multidrug-resistant ovarian cancer cells

Abstract

We have previously found that a small molecular weight (7 kDa) protein (P7) is overexpressed on the plasma membrane of ovarian cancer cells. Cell fractionation experiments described in the present report show that P7 is present in both microsomal and nuclear fractions of these cells. Indirect immunofluorescence studies confirm the presence of this protein in both plasma and nuclear membranes. The observed involvement of P7 in the proliferation of MDR ovarian cancer cells (1) and its occurrence on the nuclear membrane suggest that this protein may mediate signal transduction in these cells.