Changing protein patterns during lens cell aging in vitro.

Changes in biosynthesis of lens proteins upon culturing have been studied by one- and two-dimensional gel electrophoretic techniques. In primary cells still growing on the capsule, alpha B2-crystallin is synthesized in a relatively high amount next to the main cytoskeletal constituents actin, tubulin and vimentin. In addition, a minor amount of beta Bp seems to be synthesized too. When the cells grow off the capsule, alpha-crystallin synthesis diminishes. beta-Crystallin synthesis continues at a low rate in cells growing on plastic or in cells forming 'lentoid bodies'. When the cells are subcultured, the synthesis of actin and vimentin becomes more pronounced, while tubulin synthesis is no longer detectable after three transfers. The relative amount of vimentin decreases, as compared to actin, during aging and elongation of the cells. When the cells have been transferred ten times and have started to elongate, a 55 kDa protein doublet differing from tubulin is observed in the two-dimensional gel patterns. We observed that elongation of lens cells in culture is accompanied by an increase in the synthesis of a polypeptide of the 26 kDa region. Furthermore, a major glycoprotein is found in the 130 kDa region, but overall glycosylation of proteins seems to decrease during lens cell elongation in vitro.