title: Lateral mobility of plasma membrane lipids in normal and transformed keratinocytes.
abstract: In this study we have examined possible differentiation-dependent modulations in plasma membrane lipid properties in normal keratinocytes, SV-40 transformed keratinocytes (SVK14) and a number of squamous carcinoma (SCC) cells. In normal keratinocytes the lateral diffusion coefficient of plasma membrane lipids (D) differs significantly for cells cultured permanently under low and normal Ca2+-conditions (5.16 x 10(-9) and 3.27 x 10(-9) cm2/s, respectively). When differentiation is induced by exposing low Ca2+-cultured cells to normal Ca2+ concentrations D increases to 7.07 x 10(-9) cm2/s during the initial hours of differentiation followed by a gradual sustained decrease to values also observed in cells cultured permanently under normal Ca2+-conditions. In SCC and SVK14 cells a similar initial transient increase in lateral lipid mobility is observed upon initiation of differentiation, but, in contrast to normal keratinocytes, no sustained decrease in D is seen upon prolonged culturing under normal Ca2+ conditions. The results indicate that the deficiency of the transformed cells to respond to Ca2+-induced differentiation might involve transformation-dependent alterations in membrane structure and function.
mesh_terms: D002118:Calcium / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000378:metabolism / Q000473:pathology; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000378:metabolism / Q000473:pathology; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D003470:Culture Media; D000078404:Epidermal Cells; D004817:Epidermis / Q000378:metabolism*; D006801:Humans; D007633:Keratins; D008051:Lipid Bilayers / Q000378:metabolism*; D008563:Membrane Lipids / Q000378:metabolism*
chemical_list: D003470:Culture Media; D008051:Lipid Bilayers; D008563:Membrane Lipids; D007633:Keratins; D002118:Calcium