| Comments |
"The apparatus that deliberately destroys aberrant proteins is the proteasome,
an abundant ATP-dependent protease that constitutes nearly 1% of cell
protein. Present in many copies dispersed throughout the cytosol and the nucleus, the proteasome also destroys aberrant proteins of the endoplasmic reticulum (ER). An ER-based surveillance system detects proteins that fail either to fold or to be assembled properly after they enter the ER, and retrotranslocates them back to the cytosol for degradation (discussed in Chapter 12)." |