Heat-shock proteins as molecular chaperones

Authors

  • Jörg BECKER,

    1. Department of Biomolecular Chemistry, University of Wisconsin Medical School, Madison WI, USA
    Search for more papers by this author
  • Elizabeth A. CRAIG

    Corresponding author
    1. Department of Biomolecular Chemistry, University of Wisconsin Medical School, Madison WI, USA
      Correspondence to E. A. Craig, Department of Biomolecular Chemistry, University of Wisconsin Medical School, 1300 University Avenue, Madison, WI 53706, USA
    Search for more papers by this author

Correspondence to E. A. Craig, Department of Biomolecular Chemistry, University of Wisconsin Medical School, 1300 University Avenue, Madison, WI 53706, USA

Abstract

Functional proteins within cells are normally present in their native, completely folded form. However, vital processes of protein biogenesis such as protein synthesis and translocation of proteins into intracellular compartments require the protein to exist temporarily in an unfolded or partially folded conformation. As a consequence, regions buried when a polypeptide is in its native conformation become exposed and interact with other proteins causing protein aggregation which is deleterious to the cell. To prevent aggregation as proteins become unfolded, heat-shock proteins protect these interactive surfaces by binding to them and facilitating the folding of unfolded or nascent polypeptides. In other instances the binding of heat-shock proteins to interactive surfaces of completely folded proteins is a crucial part of their regulation. As heat shock and other stress conditions cause cellular proteins to become partially unfolded, the ability of heat-shock proteins to protect cells against the adverse effects of stress becomes a logical extension of their normal function as molecular chaperones.

Abbreviations
ER

endoplasmic reticulum

hsp

heat-shock protein

hsc

heat-shock cognate

SRP

signal recognition particle

TCP1

tailess-complex polypeptide 1

TRiC

TCP1-containing ring complex

Ancillary

Advertisement