Reciprocal Regulation of AMPK/SNF1 and Protein Acetylation

Adenosine monophosphate (AMP)-activated protein kinase (AMPK) serves as an energy sensor and master regulator of metabolism. In general, AMPK inhibits anabolism to minimize energy consumption and activates catabolism to increase ATP production. One of the mechanisms employed by AMPK to regulate metabolism is protein acetylation. AMPK regulates protein acetylation by at least five distinct mechanisms. First, AMPK phosphorylates and inhibits acetyl-CoA carboxylase (ACC) and thus regulates acetyl-CoA homeostasis. Since acetyl-CoA is a substrate for all lysine acetyltransferases (KATs), AMPK affects the activity of KATs by regulating the cellular level of acetyl-CoA. Second, AMPK activates histone deacetylases (HDACs) sirtuins by increasing the cellular concentration of NAD+, a cofactor of sirtuins. Third, AMPK inhibits class I and II HDACs by upregulating hepatic synthesis of α-hydroxybutyrate, a natural inhibitor of HDACs. Fourth, AMPK induces translocation of HDACs 4 and 5 from the nucleus to the cytoplasm and thus increases histone acetylation in the nucleus. Fifth, AMPK directly phosphorylates and downregulates p300 KAT. On the other hand, protein acetylation regulates AMPK activity. Sirtuin SIRT1-mediated deacetylation of liver kinase B1 (LKB1), an upstream kinase of AMPK, activates LKB1 and AMPK. AMPK phosphorylates and inactivates ACC, thus increasing acetyl-CoA level and promoting LKB1 acetylation and inhibition. In yeast cells, acetylation of Sip2p, one of the regulatory β-subunits of the SNF1 complex, results in inhibition of SNF1. This results in activation of ACC and reduced cellular level of acetyl-CoA, which promotes deacetylation of Sip2p and activation of SNF1. Thus, in both yeast and mammalian cells, AMPK/SNF1 regulate protein acetylation and are themselves regulated by protein acetylation.

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Enzyme cytochemistry of Candida albicans.

Journal of Histochemistry & Cytochemistry ◽

10.1177/23.10.172554 ◽

1975 ◽

Vol 23 (10) ◽

pp. 758-765 ◽

Cited By ~ 20

Author(s):

S De Nollin ◽

F Thoné ◽

M Borgers

Keyword(s):

Candida Albicans ◽

Mammalian Cells ◽

Preparation Method ◽

Adenosine Monophosphate ◽

Yeast Cells ◽

Oxidative Enzymes ◽

Thiamine Pyrophosphate ◽

Specific Marker ◽

Enzyme Cytochemistry ◽

Subcellular Organelles

The application of a new preparation method for demonstrating the activities of hydrolytic and oxidative enzymes in Candida albicans is reported. The problem of inadequate penetration of fixatives into yeast cells has been solved by sectioning solidified pellets of the cells in the presence of glutaraldehyde, a procedure that yields a fairly well preserved ultrastructure and sufficient enzyme activities. The subcellular distribution of most specific and nonspecific phosphatases and of peroxidases is at variance with that found in mammalian cells. The activities toward beta-glycerophosphate, p-nitrophenylphosphate, adenosine triphosphate, adenosine monophosphate, thiamine pyrophosphate and glucose 6-phosphate are almost exclusively confined to the central vacuolar apparatus. Oxidative and peroxidative activities are demonstrated only in mitochondria. Specific marker enzymes for endoplasmic reticulum, plasmalemma, Golgi apparatus and peroxisomes in C. albicans are not found. The possible function of the various subcellular organelles in relation to their enzymatic content is discussed.

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Class II histone deacetylases: Structure, function, and regulation

Biochemistry and Cell Biology ◽

10.1139/o01-032 ◽

2001 ◽

Vol 79 (3) ◽

pp. 243-252 ◽

Cited By ~ 148

Author(s):

Nicholas R Bertos ◽

Audrey H Wang ◽

Xiang-Jiao Yang

Keyword(s):

Structure Function ◽

Histone Deacetylases ◽

Mammalian Cells ◽

Dynamic Control ◽

Class Ii ◽

Protein Acetylation ◽

Cellular Processes ◽

Subcellular Compartmentalization ◽

Transcriptional Corepressors

Acetylation of histones, as well as non-histone proteins, plays important roles in regulating various cellular processes. Dynamic control of protein acetylation levels in vivo occurs through the opposing actions of histone acetyltransferases and histone deacetylases (HDACs). In the past few years, distinct classes of HDACs have been identified in mammalian cells. Class I members, such as HDAC1, HDAC2, HDAC3, and HDAC8, are well-known enzymatic transcriptional corepressors homologous to yeast Rpd3. Class II members, including HDAC4, HDAC5, HDAC6, HDAC7, and HDAC9, possess domains similar to the deacetylase domain of yeast Hda1. HDAC4, HDAC5, and HDAC7 function as transcriptional corepressors that interact with the MEF2 transcription factors and the N-CoR, BCoR, and CtBP corepressors. Intriguingly, HDAC4, HDAC5, and probably HDAC7 are regulated through subcellular compartmentalization controlled by site-specific phosphorylation and binding of 14-3-3 proteins; the regulation of these HDACs is thus directly linked to cellular signaling networks. Both HDAC6 and HDAC9 possess unique structural modules, so they may have special biological functions. Comprehension of the structure, function, and regulation of class II deacetylases is important for elucidating how acetylation regulates functions of histones and other proteins in vivo.Key words: histone acetylation, protein acetylation, histone deacetylase, 14-3-3 proteins.

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Acetyl-CoA carboxylase inhibition regulates microtubule dynamics and intracellular transport in cystic fibrosis epithelial cells

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00369.2018 ◽

2019 ◽

Vol 316 (6) ◽

pp. L1081-L1093

Author(s):

Sharon M. Rymut ◽

Binyu Lu ◽

Aura Perez ◽

Deborah A. Corey ◽

Kata Lamb ◽

...

Keyword(s):

Cystic Fibrosis ◽

Epithelial Cells ◽

Adverse Events ◽

Intracellular Transport ◽

Adenosine Monophosphate ◽

Cellular Level ◽

Microtubule Dynamics ◽

High Dose ◽

Acetyl Coa Carboxylase ◽

Acetyl Coa

The use of high-dose ibuprofen as an anti-inflammatory therapy in cystic fibrosis (CF) has been shown to be an effective intervention although use is limited due to potential adverse events. Identifying the mechanism of ibuprofen efficacy would aid in the development of new therapies that avoid these adverse events. Previous findings demonstrated that ibuprofen treatment restores the regulation of microtubule dynamics in CF epithelial cells through a 5′-adenosine monophosphate-activated protein kinase (AMPK)-dependent mechanism. The goal of this study is to define the AMPK pathway that leads to microtubule regulation. Here, it is identified that inhibition of acetyl-CoA carboxylase (ACC) is the key step in mediating the AMPK effect. ACC inhibition with 5-(tetradecyloxy)-2-furoic acid (TOFA) increases microtubule reformation rates in cultured and primary CF epithelial cells to wild-type (WT) rates. TOFA treatment also restores microtubule-dependent distribution of cholesterol and Rab7-positive organelles, as well as reduces expression of the proinflammatory signaling molecule RhoA to WT levels. ACC activation with citrate replicates these CF phenotypes in WT cells further supporting the role of AMPK signaling through ACC as a key mediator in CF cell signaling. It is concluded that ACC inhibition is the key step in the efficacy of AMPK activation at the cellular level and could represent a novel site of therapeutic intervention to address inflammation in CF.

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Acetylation-mediated remodeling of the nucleolus regulates cellular acetyl-CoA responses

PLoS Biology ◽

10.1371/journal.pbio.3000981 ◽

2020 ◽

Vol 18 (11) ◽

pp. e3000981

Author(s):

Ryan Houston ◽

Shiori Sekine ◽

Michael J. Calderon ◽

Fayaz Seifuddin ◽

Guanghui Wang ◽

...

Keyword(s):

Stress Responses ◽

Histone Deacetylases ◽

Culture Media ◽

Lipid Synthesis ◽

Essential Element ◽

Cell System ◽

Acetyl Coa ◽

Atp Production ◽

Wide Range ◽

A Cell

The metabolite acetyl-coenzyme A (acetyl-CoA) serves as an essential element for a wide range of cellular functions including adenosine triphosphate (ATP) production, lipid synthesis, and protein acetylation. Intracellular acetyl-CoA concentrations are associated with nutrient availability, but the mechanisms by which a cell responds to fluctuations in acetyl-CoA levels remain elusive. Here, we generate a cell system to selectively manipulate the nucleo-cytoplasmic levels of acetyl-CoA using clustered regularly interspaced short palindromic repeat (CRISPR)-mediated gene editing and acetate supplementation of the culture media. Using this system and quantitative omics analyses, we demonstrate that acetyl-CoA depletion alters the integrity of the nucleolus, impairing ribosomal RNA synthesis and evoking the ribosomal protein-dependent activation of p53. This nucleolar remodeling appears to be mediated through the class IIa histone deacetylases (HDACs). Our findings highlight acetylation-mediated control of the nucleolus as an important hub linking acetyl-CoA fluctuations to cellular stress responses.

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Acetoxy drug: protein transacetylase: A novel enzyme-mediating protein acetylation by polyphenolic peracetates

Pure and Applied Chemistry ◽

10.1351/pac200577010245 ◽

2005 ◽

Vol 77 (1) ◽

pp. 245-250 ◽

Cited By ~ 6

Author(s):

Hanumantharao G. Raj ◽

Brajendra K. Singh ◽

Ekta Kohli ◽

Bilikere S. Dwarkanath ◽

Subhash C. Jain ◽

...

Keyword(s):

Mammalian Cells ◽

Biological Effects ◽

Quantitative Structure Activity Relationship ◽

Protein Acetylation ◽

Animal Cells ◽

Acetyl Coa ◽

Qsar Studies ◽

Catalytic Activities ◽

Cytosolic Glutathione ◽

Membrane Bound

The acetylation of proteins in biological systems is largely catalyzed by specific acetyl transferases utilizing acetyl CoA as the acetyl donor. The enzymatic acetylation of proteins independent of acetyl CoA was unknown until we discovered a unique membrane-bound enzyme in mammalian cells catalyzing the transfer of acetyl groups from polyphenolic peracetates (PAs) to certain enzyme proteins, resulting in the modulation of their catalytic activities. Since for the enzyme, acetyl derivatives of several classes of polyphenols such as coumarins, flavones, chromones, and xanthones were found to be acetyl donors, the enzyme was termed as acetoxy drug: protein transacetylase (TAase). TAase was found to be ubiquitously present in tissues of several animal species and a variety of animal cells. Liver microsomal cytochrome P-450 (CYP), NADPH-cytochrome c reductase and cytosolic glutathione S-transferase (GST) were found to be the targets for TAase-catalyzed acetylation by the model acetoxy drug 7,8-diacetoxy-4-methylcoumarin (DAMC). Accordingly, the catalytic activities of CYP-linked, mixed function oxidases (MFOs) and GST were irreversibly inhibited while the reductase was remarkably activated. In this report, we have reviewed the details concerning purification and characterization of TAase and the protein acetylation by DAMC. Quantitative structure–activity relationship (QSAR) studies concerning the specificities of various PAs to liver microsomal TAase and TAase-related biological effects have also been reviewed.

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Common Principles and Specific Mechanisms of Mitophagy from Yeast to Humans

International Journal of Molecular Sciences ◽

10.3390/ijms22094363 ◽

2021 ◽

Vol 22 (9) ◽

pp. 4363

Author(s):

Rajesh Kumar ◽

Andreas S. Reichert

Keyword(s):

Stress Responses ◽

Mammalian Cells ◽

Physiological Stress ◽

Yeast Cells ◽

Loss Of Function ◽

Cellular Functions ◽

Independent Manner ◽

Common View ◽

Atp Production ◽

Atg Proteins

Mitochondria are double membrane-bound organelles in eukaryotic cells essential to a variety of cellular functions including energy conversion and ATP production, iron-sulfur biogenesis, lipid and amino acid metabolism, and regulating apoptosis and stress responses. Mitochondrial dysfunction is mechanistically linked to several neurodegenerative diseases, cancer, and ageing. Excessive and dysfunctional/damaged mitochondria are degraded by selective autophagic pathways known as mitophagy. Both budding yeast and mammals use the well-conserved machinery of core autophagy-related genes (ATGs) to execute and regulate mitophagy. In mammalian cells, the PINK1-PARKIN mitophagy pathway is a well-studied pathway that senses dysfunctional mitochondria and marks them for degradation in the lysosome. PINK1-PARKIN mediated mitophagy relies on ubiquitin-binding mitophagy adaptors that are non-ATG proteins. Loss-of-function mutations in PINK1 and PARKIN are linked to Parkinson´s disease (PD) in humans, and defective mitophagy is proposed to be a main pathomechanism. Despite the common view that yeast cells lack PINK1- and PARKIN-homologs and that mitophagy in yeast is solely regulated by receptor-mediated mitophagy, some studies suggest that a ubiquitination-dependent mitophagy pathway also exists. Here, we will discuss shared mechanisms between mammals and yeast, how mitophagy in the latter is regulated in a ubiquitin-dependent and -independent manner, and why these pathways are essential for yeast cell survival and fitness under various physiological stress conditions.

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A Narrative Review on the Role of AMPK on De Novo Lipogenesis in Non-Alcoholic Fatty Liver Disease: Evidence from Human Studies

Cells ◽

10.3390/cells10071822 ◽

2021 ◽

Vol 10 (7) ◽

pp. 1822

Author(s):

Christian von Loeffelholz ◽

Sina M. Coldewey ◽

Andreas L. Birkenfeld

Keyword(s):

Liver Disease ◽

Fatty Liver ◽

Fatty Liver Disease ◽

Mammalian Cells ◽

De Novo ◽

Adenosine Monophosphate ◽

De Novo Lipogenesis ◽

Alcoholic Fatty Liver ◽

Alcoholic Fatty Liver Disease

5′AMP-activated protein kinase (AMPK) is known as metabolic sensor in mammalian cells that becomes activated by an increasing adenosine monophosphate (AMP)/adenosine triphosphate (ATP) ratio. The heterotrimeric AMPK protein comprises three subunits, each of which has multiple phosphorylation sites, playing an important role in the regulation of essential molecular pathways. By phosphorylation of downstream proteins and modulation of gene transcription AMPK functions as a master switch of energy homeostasis in tissues with high metabolic turnover, such as the liver, skeletal muscle, and adipose tissue. Regulation of AMPK under conditions of chronic caloric oversupply emerged as substantial research target to get deeper insight into the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Evidence supporting the role of AMPK in NAFLD is mainly derived from preclinical cell culture and animal studies. Dysbalanced de novo lipogenesis has been identified as one of the key processes in NAFLD pathogenesis. Thus, the scope of this review is to provide an integrative overview of evidence, in particular from clinical studies and human samples, on the role of AMPK in the regulation of primarily de novo lipogenesis in human NAFLD.

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A murine replication protein accumulates temporarily in the heterochromatic regions of nuclei prior to initiation of DNA replication

Journal of Cell Science ◽

10.1242/jcs.108.3.927 ◽

1995 ◽

Vol 108 (3) ◽

pp. 927-934 ◽

Cited By ~ 2

Author(s):

M. Starborg ◽

E. Brundell ◽

K. Gell ◽

C. Larsson ◽

I. White ◽

...

Keyword(s):

Cell Cycle ◽

Dna Replication ◽

Mammalian Cells ◽

Mitotic Cell ◽

Yeast Cells ◽

Metaphase Chromosomes ◽

Licensing Factor ◽

Mammalian Homologue ◽

Initiation Of Dna Replication

We have analyzed the expression of the murine P1 gene, the mammalian homologue of the yeast MCM3 protein, during the mitotic cell cycle. The MCM3 protein has previously been shown to be of importance for initiation of DNA replication in Saccharomyces cerevisiae. We found that the murine P1 protein was present in the nuclei of mammalian cells throughout interphase of the cell cycle. This is in contrast to the MCM3 protein, which is located in the nuclei of yeast cells only between the M and the S phase of the cell cycle. Detailed analysis of the intranuclear localization of the P1 protein during the cell cycle revealed that it accumulates transiently in the heterochromatic regions towards the end of G1. The accumulation of the P1 protein in the heterochromatic regions prior to activation of DNA replication suggests that the mammalian P1 protein is also of importance for initiation of DNA replication. The MCM2-3.5 proteins have been suggested to represent yeast equivalents of a hypothetical replication licensing factor initially described in Xenopus. Our data support this model and indicate that the murine P1 protein could function as replication licensing factor. The chromosomal localization of the P1 gene was determined by fluorescence in situ hybridization to region 6p12 in human metaphase chromosomes.

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Functional interaction between p21rap1A and components of the budding pathway in Saccharomyces cerevisiae

Molecular and Cellular Biology ◽

10.1128/mcb.12.9.4084-4092.1992 ◽

1992 ◽

Vol 12 (9) ◽

pp. 4084-4092

Author(s):

P C McCabe ◽

H Haubruck ◽

P Polakis ◽

F McCormick ◽

M A Innis

Keyword(s):

Saccharomyces Cerevisiae ◽

Mammalian Cells ◽

Bound States ◽

Yeast Cells ◽

Temperature Sensitive ◽

Wild Type ◽

Amino Terminal ◽

Loop Region

The rap1A gene encodes a 21-kDa, ras-related GTP-binding protein (p21rap1A) of unknown function. A close structural homolog of p21rap1A (65% identity in the amino-terminal two-thirds) is the RSR1 gene product (Rsr1p) of Saccharomyces cerevisiae. Although Rsr1p is not essential for growth, its presence is required for nonrandom selection of bud sites. To assess the similarity of these proteins at the functional level, wild-type and mutant forms of p21rap1A were tested for complementation of activities known to be fulfilled by Rsr1p. Expression of p21rap1A, like multicopy expression of RSR1, suppressed the conditional lethality of a temperature-sensitive cdc24 mutation. Point mutations predicted to affect the localization of p21rap1A or its ability to cycle between GDP and GTP-bound states disrupted suppression of cdc24ts, while other mutations in the 61-65 loop region improved suppression. Expression of p21rap1A could not, however, suppress the random budding phenotype of rsr1 cells. p21rap1A also apparently interfered with the normal activity of Rsrlp, causing random budding in diploid wild-type cells, suggesting an inability of p21rap1A to interact appropriately with Rsr1p regulatory proteins. Consistent with this hypothesis, we found an Rsr1p-specific GTPase-activating protein (GAP) activity in yeast membranes which was not active toward p21rap1A, indicating that p21rap1A may be predominantly GTP bound in yeast cells. Coexpression of human Rap1-specific GAP suppressed the random budding due to expression of p21rap1A or its derivatives, including Rap1AVal-12. Although Rap1-specific GAP stimulated the GTPase of Rsr1p in vitro, it did not dominantly interfere with Rsr1p function in vivo. A chimera consisting of Rap1A1-165::Rsr1p166-272 did not exhibit normal Rsr1p function in the budding pathway. These results indicated that p21rap1A and Rsr1p share at least partial functional homology, which may have implications for p21rap1A function in mammalian cells.

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AMP-Activated Protein Kinase as a Key Trigger for the Disuse-Induced Skeletal Muscle Remodeling

International Journal of Molecular Sciences ◽

10.3390/ijms19113558 ◽

2018 ◽

Vol 19 (11) ◽

pp. 3558 ◽

Cited By ~ 13

Author(s):

Natalia Vilchinskaya ◽

Igor Krivoi ◽

Boris Shenkman

Keyword(s):

Skeletal Muscle ◽

Protein Kinase ◽

Histone Deacetylases ◽

Molecular Mechanisms ◽

Weight Bearing ◽

Mammalian Target Of Rapamycin ◽

Adenosine Monophosphate ◽

Chain Gene ◽

Mtorc1 Signaling ◽

The Impact

Molecular mechanisms that trigger disuse-induced postural muscle atrophy as well as myosin phenotype transformations are poorly studied. This review will summarize the impact of 5′ adenosine monophosphate -activated protein kinase (AMPK) activity on mammalian target of rapamycin complex 1 (mTORC1)-signaling, nuclear-cytoplasmic traffic of class IIa histone deacetylases (HDAC), and myosin heavy chain gene expression in mammalian postural muscles (mainly, soleus muscle) under disuse conditions, i.e., withdrawal of weight-bearing from ankle extensors. Based on the current literature and the authors’ own experimental data, the present review points out that AMPK plays a key role in the regulation of signaling pathways that determine metabolic, structural, and functional alternations in skeletal muscle fibers under disuse.

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