scholarly journals Location, location, location: subcellular protein partitioning in proteostasis and aging

Author(s):  
Anita V. Kumar ◽  
Louis R. Lapierre

AbstractSomatic maintenance and cell survival rely on proper protein homeostasis to ensure reliable functions across the cell and to prevent proteome collapse. Maintaining protein folding and solubility is central to proteostasis and is coordinated by protein synthesis, chaperoning, and degradation capacities. An emerging aspect that influences proteostasis is the dynamic protein partitioning across different subcellular structures and compartments. Here, we review recent literature related to nucleocytoplasmic partitioning of proteins, nuclear and cytoplasmic quality control mechanisms, and their impact on the development of age-related diseases. We also highlight new points of entry to modulate spatially-regulated proteostatic mechanisms to delay aging.

2016 ◽  
Vol 213 (6) ◽  
pp. 693-704 ◽  
Author(s):  
Natalia Sikorska ◽  
Leticia Lemus ◽  
Auxiliadora Aguilera-Romero ◽  
Javier Manzano-Lopez ◽  
Howard Riezman ◽  
...  

Endoplasmic reticulum (ER) quality control mechanisms target terminally misfolded proteins for ER-associated degradation (ERAD). Misfolded glycophosphatidylinositol-anchored proteins (GPI-APs) are, however, generally poor ERAD substrates and are targeted mainly to the vacuole/lysosome for degradation, leading to predictions that a GPI anchor sterically obstructs ERAD. Here we analyzed the degradation of the misfolded GPI-AP Gas1* in yeast. We could efficiently route Gas1* to Hrd1-dependent ERAD and provide evidence that it contains a GPI anchor, ruling out that a GPI anchor obstructs ERAD. Instead, we show that the normally decreased susceptibility of Gas1* to ERAD is caused by canonical remodeling of its GPI anchor, which occurs in all GPI-APs and provides a protein-independent ER export signal. Thus, GPI anchor remodeling is independent of protein folding and leads to efficient ER export of even misfolded species. Our data imply that ER quality control is limited for the entire class of GPI-APs, many of them being clinically relevant.


2019 ◽  
Vol 18 (10) ◽  
pp. 2078-2088 ◽  
Author(s):  
Lu Yang ◽  
Ye Cao ◽  
Jing Zhao ◽  
Yanshan Fang ◽  
Nan Liu ◽  
...  

Aging is characterized by a gradual deterioration in proteome. However, how protein dynamics that changes with normal aging and in disease is less well understood. Here, we profiled the snapshots of aging proteome in Drosophila, from head and muscle tissues of post-mitotic somatic cells, and the testis of mitotically-active cells. Our data demonstrated that dysregulation of proteome homeostasis, or proteostasis, might be a common feature associated with age. We further used pulsed metabolic stable isotope labeling analysis to characterize protein synthesis. Interestingly, this study determined an age-modulated decline in protein synthesis with age, particularly in the pathways related to mitochondria, neurotransmission, and proteostasis. Importantly, this decline became dramatically accelerated in Pink1 mutants, a Drosophila model of human age-related Parkinson's disease. Taken together, our multidimensional proteomic study revealed tissue-specific protein dynamics with age, highlighting mitochondrial and proteostasis-related proteins. We suggest that declines in proteostasis and mitochondria early in life are critical signals prior to the onset of aging and aging-associated diseases.


2014 ◽  
Vol 7 (3) ◽  
pp. 331-341 ◽  
Author(s):  
S. P. Ferris ◽  
V. K. Kodali ◽  
R. J. Kaufman

2021 ◽  
Author(s):  
Yoon-Mo Yang ◽  
Katrin Karbstein

Although ribosome assembly is quality controlled to maintain protein homeostasis, different ribosome populations have been described. How these form, especially under stress conditions that impact energy levels and stop the energy-intensive production of ribosomes, remains unknown. Here we demonstrate how a physiologically relevant ribosome population arises during high Na+ and pH stress via dissociation of Rps26 from fully assembled ribosomes to enable a translational response to these stresses. The chaperone Tsr2 releases Rps26 in the presence of high Na or pH in vitro and is required for Rps26 release in vivo. Moreover, Tsr2 stores free Rps26 and promotes re-incorporation of the protein, thereby repairing the subunit after the stress subsides. Our data implicate a residue in Rps26 involved in Diamond Blackfan Anemia in mediating the effects of Na+. These data demonstrate how different ribosome populations can arise rapidly, without major energy input, and without bypass of quality control mechanisms.


2020 ◽  
Author(s):  
Chi-Ning Chuang ◽  
Tai-Ting Woo ◽  
Shih-Ying Tsai ◽  
Wan-Chen Li ◽  
Chia-Ling Chen ◽  
...  

AbstractIntrinsically disordered regions (IDRs) are protein sequences lacking fixed or ordered three-dimensional structures. Many IDRs are endowed with important molecular functions such as physical interactions, posttranslational modifications or solubility enhancement. We reveal that several biologically important IDRs can act as N-terminal fusion carriers to promote target protein folding or protein quality control, thereby enhancing protein expression. This nanny function has a reasonably strong correlation with high S/T/Q/N amino acid content in IDRs and it is tunable (e.g., via phosphorylation) to regulate protein homeostasis. We propose a hypothesis that “N-terminal intrinsic disorder facilitates abundance” (NIDFA) to explain how some yeast proteins use their N-terminal IDRs (N-IDRs) to generate high levels of protein product. These N-IDRs are versatile toolkits for functional divergence in signaling and evolution.SignificanceDisorder within an otherwise well-structured protein is mostly found in intrinsically disordered regions (IDRs). IDRs can provide many advantages to proteins, including: (1) mediating protein-protein or protein-peptide interactions by adopting different conformations; (2) facilitating protein regulation via diverse posttranslational modifications; and (3) regulating the half-lives of proteins that have been targeted for proteasomal degradation. Here, we report that several biologically important IDRs in S. cerevisiae can act as N-terminal fusion carriers to promote target protein folding or protein quality control, thereby enhancing protein expression. We demonstrate by genetic and bioinformatic analyses that this nanny function is well correlated with high content of serine, threonine, glutamine and asparagine in IDRs and is tunable (e.g., via phosphorylation) to regulate protein homeostasis.


Author(s):  
Andreas Zimmermann ◽  
Corina Madreiter-Sokolowski ◽  
Sarah Stryeck ◽  
Mahmoud Abdellatif

Human life expectancy continues to grow globally, and so does the prevalence of age-related chronic diseases, causing a huge medical and economic burden on society. Effective therapeutic options for these disorders are scarce, and even if available, are typically limited to a single comorbidity in a multifaceted dysfunction that inevitably affects all organ systems. Thus, novel therapies that target fundamental processes of aging itself are desperately needed. In this article, we summarize current strategies that successfully delay aging and related diseases by targeting mitochondria and protein homeostasis. In particular, we focus on autophagy, as a fundamental proteostatic process that is intimately linked to mitochondrial quality control. We present genetic and pharmacological interventions that effectively extend health- and life-span by acting on specific mitochondrial and pro-autophagic molecular targets. In the end, we delve into the crosstalk between autophagy and mitochondria, in what we refer to as the mitochondria-proteostasis axis, and explore the prospect of targeting this crosstalk to harness maximal therapeutic potential of anti-aging interventions.


2020 ◽  
Vol 49 (1) ◽  
pp. 41-67 ◽  
Author(s):  
Linhao Ruan ◽  
Yuhao Wang ◽  
Xi Zhang ◽  
Alexis Tomaszewski ◽  
Joshua T. McNamara ◽  
...  

Mitochondria are essential organelles in eukaryotes. Most mitochondrial proteins are encoded by the nuclear genome and translated in the cytosol. Nuclear-encoded mitochondrial proteins need to be imported, processed, folded, and assembled into their functional states. To maintain protein homeostasis (proteostasis), mitochondria are equipped with a distinct set of quality control machineries. Deficiencies in such systems lead to mitochondrial dysfunction, which is a hallmark of aging and many human diseases, such as neurodegenerative diseases, cardiovascular diseases, and cancer. In this review, we discuss the unique challenges and solutions of proteostasis in mitochondria. The import machinery coordinates with mitochondrial proteases and chaperones to maintain the mitochondrial proteome. Moreover, mitochondrial proteostasis depends on cytosolic protein quality control mechanisms during crises. In turn, mitochondria facilitate cytosolic proteostasis. Increasing evidence suggests that enhancing mitochondrial proteostasis may hold therapeutic potential to protect against protein aggregation–associated cellular defects.


2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Yifei Zhou ◽  
Xueqing Wang ◽  
Mengjiao Song ◽  
Zhidong He ◽  
Guizhong Cui ◽  
...  

Abstract Macroautophagy, a key player in protein quality control, is proposed to be systematically impaired in distinct tissues and causes coordinated disruption of protein homeostasis and ageing throughout the body. Although tissue-specific changes in autophagy and ageing have been extensively explored, the mechanism underlying the inter-tissue regulation of autophagy with ageing is poorly understood. Here, we show that a secreted microRNA, mir-83/miR-29, controls the age-related decrease in macroautophagy across tissues in Caenorhabditis elegans. Upregulated in the intestine by hsf-1/HSF1 with age, mir-83 is transported across tissues potentially via extracellular vesicles and disrupts macroautophagy by suppressing CUP-5/MCOLN, a vital autophagy regulator, autonomously in the intestine as well as non-autonomously in body wall muscle. Mutating mir-83 thereby enhances macroautophagy in different tissues, promoting protein homeostasis and longevity. These findings thus identify a microRNA-based mechanism to coordinate the decreasing macroautophagy in various tissues with age.


2021 ◽  
Author(s):  
Ning Wang ◽  
Yifan Wang ◽  
Qian Zhao ◽  
Xiang Zhang ◽  
Chao Peng ◽  
...  

Protein homeostasis in plastids is strategically regulated by the protein quality control system involving multiple chaperones and proteases, among them the Clp protease. We determined the structure of the chloroplast ClpP complex from Chlamydomonas reinhardtiiby cryo-EM. ClpP contains two heptameric catalytic rings without any symmetry. The top ring contains one ClpR6, three ClpP4 and three ClpP5 subunits while the bottom ring is composed of three ClpP1C subunits and one each of the ClpR1-4 subunits. ClpR3, ClpR4 and ClpT4 subunits connect the two rings and stabilize the complex. The chloroplast Cpn11/20/23 co-chaperonin, a co-factor of Cpn60, forms a cap on the top of ClpP by protruding mobile loops into hydrophobic clefts at the surface of the top ring. The co-chaperonin repressed ClpP proteolytic activity in vitro. By regulating Cpn60 chaperone and ClpP protease activity, the co-chaperonin may play a role in coordinating protein folding and degradation in the chloroplast.


Genetics ◽  
2020 ◽  
Vol 215 (4) ◽  
pp. 889-901 ◽  
Author(s):  
Thorsten Hoppe ◽  
Ehud Cohen

Sustaining a healthy proteome is a lifelong challenge for each individual cell of an organism. However, protein homeostasis or proteostasis is constantly jeopardized since damaged proteins accumulate under proteotoxic stress that originates from ever-changing metabolic, environmental, and pathological conditions. Proteostasis is achieved via a conserved network of quality control pathways that orchestrate the biogenesis of correctly folded proteins, prevent proteins from misfolding, and remove potentially harmful proteins by selective degradation. Nevertheless, the proteostasis network has a limited capacity and its collapse deteriorates cellular functionality and organismal viability, causing metabolic, oncological, or neurodegenerative disorders. While cell-autonomous quality control mechanisms have been described intensely, recent work on Caenorhabditis elegans has demonstrated the systemic coordination of proteostasis between distinct tissues of an organism. These findings indicate the existence of intricately balanced proteostasis networks important for integration and maintenance of the organismal proteome, opening a new door to define novel therapeutic targets for protein aggregation diseases. Here, we provide an overview of individual protein quality control pathways and the systemic coordination between central proteostatic nodes. We further provide insights into the dynamic regulation of cellular and organismal proteostasis mechanisms that integrate environmental and metabolic changes. The use of C. elegans as a model has pioneered our understanding of conserved quality control mechanisms important to safeguard the organismal proteome in health and disease.


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