Membrane dynamics in human leukemia and lymphoma cells. pH dependency of diphenylhexatriene fluorescence polarization

Membrane dynamics of human leukemia and lymphoma cell lines were analyzed by investigating the effect of pH on fluorescence polarization (P) of the lipophilic probe diphenylhexatriene (DPH). The degree of P varied as a function of pH, depending on the cell lines. These variations were not detected in phospholipid vesicles. In addition, they were prevented by treatments with glutaraldehyde, sodium azide or phenylmethylsulfanyl fluoride, a specific protease inhibitor. Therefore, these P value changes might be influenced by protein modification.