Chaperones
Chapters
Co-Chaperones of the Endoplasmic Reticulum
Johanna Dudek, Martin Jung, Andreas Weitzmann, Markus Greiner and Richard Zimmermann
The rough endoplasmic reticulum (ER) plays a central role in the biogenesis of most extracellular and many organellar proteins in eukaryotic cells. Therefore, this organelle comprises molecular chaperones that are involved in import, folding/assembly, export, and degradation of polypeptides in m...
Do Hsp40s Act As Chaperones or Co-Chaperones?
Meredith F.N. Rosser and Douglas M. Cyr
The Hsp70 family plays an essential role in cellular protein metabolism by acting as a polypeptide binding and release factor that interacts with nonnative regions of proteins at different stages of their life cycles.1 Hsp40 proteins not only act as co-chaperones to facilitate complex formatio...
From Creator to Terminator: Co-Chaperones That Link Molecular Chaperones to the Ubiquitin/Proteasome System
Jörg Höhfeld, Karsten Böhse, Markus Genau and Britta Westhoff
Molecular chaperones are well known as intracellular mediators of protein folding. An active participation in protein degradation only recently emerged from the functional characterization of certain co-chaperones. In the light of these novel findings long held views regarding the interplay of c...
Functions of the Hsp90-Binding FKBP Immunophilins
Marc B. Cox and David F. Smith
Hsp90 functionally interacts with a broad array of client proteins, but in every case examined Hsp90 is accompanied by one or more cochaperones. One class of cochaperone contains a tetratricopeptide repeat domain that targets the cochaperone to the C-terminal region of Hsp90. Within this class are...
Hop: An Hsp70/Hsp90 Co-Chaperone That Functions within and beyond Hsp70/Hsp90 Protein Folding Pathways
Sheril Daniel, Csaba Söti, Peter Csermely, Graeme Bradley and Gregory L Blatch
Molecular chaperones and their co-chapterones are crucial for the facilitation of efficient protein folding, and prevention of denaturation and aggregation of nascent polypeptides. Hsp70/Hsp90 organizing protein (Hop), a co-chapterone of the two major molecular chaperones, heat shock protein 7...
Nucleotide Exchange Factors for Hsp70 Molecular Chaperones
Jeffrey L. Brodsky and Andreas Bracher
Hsp70 molecular chaperones hydrolyze and re-bind ATP concomitant with the binding and release of aggregation-prone protein substrates. As a result, Hsp70s can enhance protein folding and degradation, the assembly of multi-protein complexes, and the catalytic activity of select enzymes. The abilit...
The Chaperone and Co-Chaperone Activities of Cdc37 during Protein Kinase Maturation
Avrom J. Caplan
Eukaryotic protein kinases fold in the cytosol in association with the Hsp90 molecular chaperone machine. This machine comprises a large number of chaperones and co-chaperones, among them Cdc37, which is essential for protein kinase maturation. Cdc37 interacts with protein kinases via their ca...
The Evolution and Function of Co-Chaperones in Mitochondria
Dejan Bursac and Trevor Lithgow
Mitochondrial chaperones mediate and affect critical organellar processes, essential for cellular function. These chaperone systems have both prokaryotic and eukaryotic features. While some of the mitochondrial co-chaperones have clear homologues in prokaryotes, some are unique to eukaryotes a...
The Role of Hsp70 and Its Co-Chaperones in Protein Misfolding, Aggregation and Disease
Jacqueline van der Spuy, Michael E. Cheetham and J. Paul Chapple
Molecular chaperones and their associated co-chaperones are essential in health and disease as they are key facilitators of protein folding, quality control and function. In particular, the Hsp70 molecular chaperone networks have been associated with neurodegenerative diseases caused by aberra...
The Roles of GroES As a Co-Chaperone for GroEL
Han Liu and Peter A Lund
GroES works with the essential chaperone GroEL to mediate the folding of certain proteins from an unfolded or partially folded state. These two proteins form the only essential chaperone machine in E. coli. Both proteins have seven-fold symmetry. GroES acts by binding to one end of the GroEL c...
UNC-45: A Chaperone for Myosin and a Co-Chaperone for Hsp90
Odutayo O. Odunuga and Henry F. Epstein
UNC-45 is a prototype of the protein family characterized by the presence of the C-terminal UCS (UNC-45/CRO1/She4p) domain. These proteins function in vari- ous important actin- and myosin-dependent cellular processes that include myofibril organization and muscle functions, cell differentiatio...
