CD95 (FAS APO-1)-INDUCED APOPTOSIS RESULTS IN LOSS OF GLUCOSE-TRANSPORTER FUNCTION/

Treatment of activated human T cells with CD95 (Fas/Apo-1) ligand or A bs against CD95 results in apoptotic cell death, Although cellular res ponses to CD95 ligation have been described in some detail, the early molecular events that result in T cell death are only now beginning to be elucidated. Using Jurkat cells as a model of activated human T cel ls, we have investigated the effects of CD95 ligation on glucose trans port and on glucose transporter function, We show that within minutes of CD95 activation, the ability to transport glucose across the plasma membrane is compromised and that transient exposure to Abs against CD 95 for as little as 3 min results in reduced glucose transport and (4, 5-dimethyithiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) response s measured at 16 h. The effects of CD95 ligation on glucose transport are shown to be associated with loss of affinity of glucose transporte rs for glucose without altered maximum velocity and without changes in the cell surface expression of Glut 1, the predominant glucose transp orter isotype on Jurkat cells, These results support a model of CD95-i nduced cell death that, at least in its early stages, does not depend on signaling to the nucleus or on macromolecular synthesis, Acute regu lation of glucose transport is proposed to be an early effector mechan ism in CD95-induced apoptotic cell death.