title: Changes in activity and amount of active elongation factor 1 alpha in aging and immortal human fibroblast cultures.
abstract: Stoichiometrically estimated amounts of active elongation factor, EF-1 alpha, remain constant in serially passaged Phase II cultures of human fibroblasts, MRC-5, but decrease by 45% towards the end (Phase III) of their lifespan. Catalytic activity of EF-1 alpha is also reduced by 35% in Phase III old cells. The SV40 transformed immortal cell line MRC-5V2 has 30% higher levels of active EF-1 alpha without significant increase in its catalytic activity. Low-serum-associated G1 arrest of normal and transformed cells reduces amounts of active EF-1 alpha by 35% and 20%, respectively. Catalytic activity, however, is reduced rapidly only in G1 arrested normal cells and not in transformed cells. Even though the cell cycle-related changes are reversible both in normal and transformed cells, the age-related decline in amounts of active EF-1 alpha and its activity are irreversible and, most probably, crucial.
mesh_terms: D002384:Catalysis; D002460:Cell Line; D002472:Cell Transformation, Viral; D005347:Fibroblasts / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors / Q000032:analysis / Q000378:metabolism*; D013539:Simian virus 40; D013997:Time Factors
chemical_list: D020648:Peptide Elongation Factor 1; D010445:Peptide Elongation Factors