Integrating condensates into protein lifespan - From birth to death.

Proper protein production is an essential biological process for all known living organisms. The cell depends on a functional protein homeostasis, or proteostasis, network to facilitate proper gene expression, transcription, translation, polypeptide folding, and degradation. Several condensates are involved in the "birth" and maturation of newly synthesized proteins. In conditions of cellular stress, gene expression and protein production are altered, and protein degradation often increases. Under various types of cellular stress, new condensates often form. This review will highlight the condensates that are involved in the protein lifespan. This includes condensates that regulate gene expression, protein translation, sequester misfolded proteins, and those associated with protein degradation. We will summarize what is known about these condensates under unstressed conditions, and how their regulation changes under stressed conditions. Understanding the functions and regulation of condensates during the protein life cycle will be critical to determining how things go awry in disease.