Plasma membrane motility of cultured human glia cells in phase II and III.

A human diploid glia line (U-787 CG) was cultured on haptotactic islands using a miniclone method recently described. The surface morphology and motility pattern of the cells were studied using timelapse cinemicrophotography and scanning electron microscopy. Proliferating cells showed locomotion and ruffling activity with intermittent associated macropinocytosis. Non-dividers, viz, cells which had not divided 10 days after seeding on the haptotactic islands, were immobile, larger than the dividers, rather flat with few microvilli, and showed only very occasional ruffles almost completely without associated macropinocytosis. Our present findings show that phase III cells growing singly on haptotactic islands in serum-containing medium behave like phase II cells starved of growth factors or density growth inhibited. The results corroborate the theory that stationary cells have depressed ruffling activity and associated macropinocytosis as compared with proliferating cells.