Intracellular protein degradation

Intracellular protein degradation.

The steady-state level of protein in the whole body or in individual tissues is governed not only by the rate of synthesis but by the rate of degradation. Thus protein turnover is a composite term that relates the synthetic and degradative processes. We now have a detailed knowledge of the machinery for synthesizing polypeptide chains and of the requirement for energy to drive the operation, an...

Intracellular Protein Degradation

Between the 1950s and 1980s, scientists were focusing mostly on how the genetic code is transcribed to RNA and translated to proteins, but how proteins are degraded has remained a neglected research area. With the discovery of the lysosome by Christian de Duve it was assumed that cellular proteins are degraded within this organelle. Yet, several independent lines of experimental evidence strong...

Intracellular protein degradation

Intracellular protein degradation and its therapeutic implications.

Lysosomes are produced in Golgi apparatus for degradation of ingested products. For example, bacteria taken up by phagocytosis are enclosed in vacuoles, which then fuse with vesicles containing lysosomal enzymes (primary lysosomes). As the pH becomes more acidic, enzymes become activated and the vacuole becomes a secondary lysosome degrading the bacterium. Lysosomes also play a key role in dest...

Intracellular protein degradation in serum-deprived human fibroblasts.

IMR90 human fibroblasts were labelled by incubation of cells for 48 h in medium containing 10% serum and [3H]leucine. The labelled protein was degraded at a rate of 1%/h during a subsequent incubation in medium with 10% serum. Incubation in medium without serum caused a transient enhancement of the degradation of endogenous protein, which was also found in cells labelled in medium without serum...