Abstract
Protein folding is a spontaneous process. However, under physiological conditions, proteins are inherently unstable, and the protein concentrations in living cells favor unspecific interactions between partially folded proteins. Thus, the cellular proteome requires the assistance of helper factors, the molecular chaperones, for quality control and the maintenance of protein homeostasis. This series of reviews delves into how these molecular machines work in the eukaryotic cell, how they convey resilience to life, how these functions have allowed expansion of the protein universe, and how we can target them for therapeutic purposes. Together, they present the progress made in recent years in our understanding of one of the most fundamental aspects of life.