The Giant Protein Titin as an Integrator of Myocyte Signaling Pathways

Physiology ◽  
2010 ◽  
Vol 25 (3) ◽  
pp. 186-198 ◽  
Author(s):  
Wolfgang A. Linke ◽  
Martina Krüger

The giant muscle protein titin, the “backbone” of the sarcomere, harbors a complex molecular spring whose stiffness is variably tuned in health and disease. Titin is increasingly recognized as a crucial integrator of diverse myocyte signaling pathways. The titin-associated signalosome includes hotspots of protein-protein interactions important for the regulation of protein quality-control mechanisms, hypertrophic gene activation, and mechanosensing.

2021 ◽  
pp. 153537022199981
Author(s):  
Chamithi Karunanayake ◽  
Richard C Page

The chaperone heat shock protein 70 (Hsp70) and its network of co-chaperones serve as a central hub of cellular protein quality control mechanisms. Domain organization in Hsp70 dictates ATPase activity, ATP dependent allosteric regulation, client/substrate binding and release, and interactions with co-chaperones. The protein quality control activities of Hsp70 are classified as foldase, holdase, and disaggregase activities. Co-chaperones directly assisting protein refolding included J domain proteins and nucleotide exchange factors. However, co-chaperones can also be grouped and explored based on which domain of Hsp70 they interact. Here we discuss how the network of cytosolic co-chaperones for Hsp70 contributes to the functions of Hsp70 while closely looking at their structural features. Comparison of domain organization and the structures of co-chaperones enables greater understanding of the interactions, mechanisms of action, and roles played in protein quality control.


Molecules ◽  
2018 ◽  
Vol 23 (5) ◽  
pp. 1219 ◽  
Author(s):  
Sophia Wedel ◽  
Maria Manola ◽  
Maria Cavinato ◽  
Ioannis Trougakos ◽  
Pidder Jansen-Dürr

2020 ◽  
Vol 11 ◽  
Author(s):  
Sumita Mishra ◽  
Brittany L. Dunkerly-Eyring ◽  
Gizem Keceli ◽  
Mark J. Ranek

2016 ◽  
Vol 60 (2) ◽  
pp. 213-225 ◽  
Author(s):  
Wolfgang Voos ◽  
Witold Jaworek ◽  
Anne Wilkening ◽  
Michael Bruderek

Mitochondria are essential constituents of a eukaryotic cell by supplying ATP and contributing to many mayor metabolic processes. As endosymbiotic organelles, they represent a cellular subcompartment exhibiting many autonomous functions, most importantly containing a complete endogenous machinery responsible for protein expression, folding and degradation. This article summarizes the biochemical processes and the enzymatic components that are responsible for maintaining mitochondrial protein homoeostasis. As mitochondria lack a large part of the required genetic information, most proteins are synthesized in the cytosol and imported into the organelle. After reaching their destination, polypeptides must fold and assemble into active proteins. Under pathological conditions, mitochondrial proteins become misfolded or damaged and need to be repaired with the help of molecular chaperones or eventually removed by specific proteases. Failure of these protein quality control mechanisms results in loss of mitochondrial function and structural integrity. Recently, novel mechanisms have been identified that support mitochondrial quality on the organellar level. A mitochondrial unfolded protein response allows the adaptation of chaperone and protease activities. Terminally damaged mitochondria may be removed by a variation of autophagy, termed mitophagy. An understanding of the role of protein quality control in mitochondria is highly relevant for many human pathologies, in particular neurodegenerative diseases.


Science ◽  
2019 ◽  
Vol 365 (6451) ◽  
pp. 342-347 ◽  
Author(s):  
F. Frottin ◽  
F. Schueder ◽  
S. Tiwary ◽  
R. Gupta ◽  
R. Körner ◽  
...  

The nuclear proteome is rich in stress-sensitive proteins, which suggests that effective protein quality control mechanisms are in place to ensure conformational maintenance. We investigated the role of the nucleolus in this process. In mammalian tissue culture cells under stress conditions, misfolded proteins entered the granular component (GC) phase of the nucleolus. Transient associations with nucleolar proteins such as NPM1 conferred low mobility to misfolded proteins within the liquid-like GC phase, avoiding irreversible aggregation. Refolding and extraction of proteins from the nucleolus during recovery from stress was Hsp70-dependent. The capacity of the nucleolus to store misfolded proteins was limited, and prolonged stress led to a transition of the nucleolar matrix from liquid-like to solid, with loss of reversibility and dysfunction in quality control. Thus, we suggest that the nucleolus has chaperone-like properties and can promote nuclear protein maintenance under stress.


2016 ◽  
Vol 9 (3) ◽  
pp. a023523 ◽  
Author(s):  
Tatyana Dubnikov ◽  
Tziona Ben-Gedalya ◽  
Ehud Cohen

2020 ◽  
Vol 11 ◽  
Author(s):  
Jie Li ◽  
Jianqiu Zou ◽  
Rodney Littlejohn ◽  
Jinbao Liu ◽  
Huabo Su

Defects in protein quality control have been increasingly recognized as pathogenic factors in the development of heart failure, a persistent devastating disease lacking efficacious therapies. Ubiquitin and ubiquitin-like proteins, a family of post-translational modifying polypeptides, play important roles in controlling protein quality by maintaining the stability and functional diversity of the proteome. NEDD8 (neural precursor cell expressed, developmentally downregulated 8), a small ubiquitin-like protein, was discovered two decades ago but until recently the biological significance of NEDD8 modifications (neddylation) in the heart has not been appreciated. In this review, we summarize the current knowledge of the biology of neddylation, highlighting several mechanisms by which neddylation regulates the function of its downstream targets, and discuss the expanding roles for neddylation in cardiac physiology and disease, with an emphasis on cardiac protein quality control. Finally, we outline challenges linked to the study of neddylation in health and disease.


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