Degradation of endocytosed proteins is unaltered in senescent human fibroblasts.
We compared the abilities of young and senescent fibroblasts to take up and degrade [3H]ribonuclease A (native and oxidized), [3H]ribonuclease4-13, [3H]hemoglobin, [3H]glyceraldehyde-3-phosphate dehydrogenase, [3H]beta-galactosidase, [3H]glycogen phosphorylase, and [125I]serum albumin. The endocytic uptake of these proteins ranged from fluid-phase to predominantly absorptive. Intralysosomal degradation rates of the different endocytosed proteins varied by an order of magnitude, but in no case was there a difference between cultures of young and senescent fibroblasts.
Gurley
R
R
Department of Physiology, Tufts University School of Medicine, Boston, MA 02111.
Dice
J F
JF
D000375:Aging / Q000378:metabolism*; D002478:Cells, Cultured; D004705:Endocytosis; D005347:Fibroblasts / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism / Q000493:pharmacokinetics; D006454:Hemoglobins / Q000378:metabolism / Q000493:pharmacokinetics; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D006005:Phosphorylases / Q000378:metabolism / Q000493:pharmacokinetics; D011506:Proteins / Q000378:metabolism* / Q000493:pharmacokinetics; D012259:Ribonuclease, Pancreatic / Q000378:metabolism / Q000493:pharmacokinetics; D012260:Ribonucleases / Q000378:metabolism / Q000493:pharmacokinetics; D012709:Serum Albumin / Q000378:metabolism / Q000493:pharmacokinetics; D013395:Sucrose / Q000378:metabolism / Q000493:pharmacokinetics; D001616:beta-Galactosidase / Q000378:metabolism / Q000493:pharmacokinetics
D006454:Hemoglobins; D011506:Proteins; D012709:Serum Albumin; D013395:Sucrose; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases; D006005:Phosphorylases; D012260:Ribonucleases; D012259:Ribonuclease, Pancreatic; D001616:beta-Galactosidase