GLUCOSE-REGULATED MEMBRANE-PROPERTIES OF UNTRANSFORMED AND VIRUS-TRANSFORMED BHK21-CELLS

BHK21 fibroblasts transformed by hamster sarcoma virus have a higher rate of uptake of hexoses than their untransformed counterparts, and therefore rapidly exhaust glucose from the culture medium. The effects of culturing normal and transformed BHK cells, both in limiting and in excess glucose, on several membrane properties related to malignant transformation have been studied. The increase in the rate of hexose uptake in transformed cells is partially but not entirely dependent on extracellular glucose concentration. Two transformation-increased membrane proteins of molecular weights 95 000 and 78 000 are shown to be regulated by extracellular glucose concentration in both normal and transformed cells. The loss of LETS-protein, the high density of intramembranous particles, the increase in the amount of a 177K integral plasma membrane protein and the increase in the amount of high molecular weight surface glycopeptides in transformed cells, are not related to glucose depletion of the medium. Beside LETS, another iodinated protein, of molecular weight 160 000, is decreased in transformed cells. The exposure of this protein increased in both normal and transformed cells when arrested in G1 by asparagine deprivation. © 1979.