The Not4 RING E3 Ligase: A Relevant Player in Cotranslational Quality Control

Figure 1

Role of the molecular chaperones in protein folding, removal from aggregates, and delivery to the proteasome. Newly synthesized proteins start to fold cotranslationally, and they are assisted by ribosome-associated chaperones. Not all proteins reach their native state after synthesis, and they are assisted by ATP-dependent chaperones of the Hsp70 family. They will then either fold into their native state or require yet other chaperones such as Hsp60 or Hsp90. Some proteins might not fold and instead aggregate. They can subsequently be refolded or delivered to the UPS system, in both cases with the help of molecular chaperones. Alternatively they might form toxic amyloid fibrils (figure adapted from [14]).