Nitric oxide inhibits the ATPase activity of the chaperone-like AAA+ ATPase CDC48, a target for S-nitrosylation in cryptogein signalling in tobacco cells

2012 ◽  
Vol 447 (2) ◽  
pp. 249-260 ◽  
Author(s):  
Jéremy Astier ◽  
Angélique Besson-Bard ◽  
Olivier Lamotte ◽  
Jean Bertoldo ◽  
Stéphane Bourque ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Oxidative Modification ◽  
Tobacco Cells ◽  
No Donors ◽  
Defence Reaction ◽  
Aaa Atpase ◽  
Proteomic Approach ◽  
D2 Domain

NO has important physiological functions in plants, including the adaptative response to pathogen attack. We previously demonstrated that cryptogein, an elicitor of defence reaction produced by the oomycete Phytophthora cryptogea, triggers NO synthesis in tobacco. To decipher the role of NO in tobacco cells elicited by cryptogein, in the present study we performed a proteomic approach in order to identify proteins undergoing S-nitrosylation. We provided evidence that cryptogein induced the S-nitrosylation of several proteins and identified 11 candidates, including CDC48 (cell division cycle 48), a member of the AAA+ ATPase (ATPase associated with various cellular activities) family. In vitro, NtCDC48 (Nicotiana tabacum CDC48) was shown to be poly-S-nitrosylated by NO donors and we could identify Cys110, Cys526 and Cys664 as a targets for S-nitrosylation. Cys526 is located in the Walker A motif of the D2 domain, that is involved in ATP binding and was previously reported to be regulated by oxidative modification in Drosophila. We investigated the consequence of NtCDC48 S-nitrosylation and found that NO abolished NtCDC48 ATPase activity and induced slight conformation changes in the vicinity of Cys526. Similarly, substitution of Cys526 by an alanine residue had an impact on NtCDC48 activity. More generally, the present study identified CDC48 as a new candidate for S-nitrosylation in plants facing biotic stress and further supports the importance of Cys526 in the regulation of CDC48 by oxidative/nitrosative agents.

Cellular Samurai: katanin and the severing of microtubules

2000 ◽  
Vol 113 (16) ◽  
pp. 2821-2827 ◽  
Author(s):  
L. Quarmby
Keyword(s):  
Epithelial Cells ◽  
Essential Role ◽  
Aaa Atpase ◽  
C Elegans ◽  
Microtubule Severing ◽  
Biochemical Studies ◽  
New Evidence

Recent biochemical studies of the AAA ATPase, katanin, provide a foundation for understanding how microtubules might be severed along their length. These in vitro studies are complemented by a series of recent reports of direct in vivo observation of microtubule breakage, which indicate that the in vitro phenomenon of catalysed microtubule severing is likely to be physiological. There is also new evidence that microtubule severing by katanin is important for the production of non-centrosomal microtubules in cells such as neurons and epithelial cells. Although it has been difficult to establish the role of katanin in mitosis, new genetic evidence indicates that a katanin-like protein, MEI-1, plays an essential role in meiosis in C. elegans. Finally, new proteins involved in the severing of axonemal microtubules have been discovered in the deflagellation system of Chlamydomonas.

Calcium ATPase and intestinal calcium transport in uremic rats

1980 ◽  
Vol 238 (5) ◽  
pp. G424-G428
Author(s):  
H. Schiffl ◽  
U. Binswanger
Keyword(s):  
Enzyme Activity ◽  
Atpase Activity ◽  
Calcium Transport ◽  
Calcium Atpase ◽  
Intestinal Calcium Transport ◽  
Identical Response ◽  
Close Relationship ◽  
Intact Rats

Calcium ATPase, an enzyme involved in intestinal calcium transport, was measured in homogenates of duodenal mucosal scrapings of normal and uremic rats. The effects of calcium deprivation and treatment with 1 alpha,25-dihydroxycholecalciferol [1,25-(OH)2D3] were investigated as well. Uremia decreased the enzyme activity and impaired the rise after calcium deprivation as observed in intact rats. The 1,25-(OH)2D3 treatment increased the enzyme activity in uremic animals and resulted in an identical response to calcium deprivation as observed in intact rats; parathyroidectomy abolished this effect. A striking correlation between everted duodenal gut sac calcium transport and calcium ATPase activity could be demonstrated for all groups of rats studied. It is concluded that the calcium ATPase activity is linked to the production of 1,25-(OH)2D3 as well as to an additional factor, probably parathyroid hormone. The close relationship between enzyme activity and in vitro calcium transport, even during constant physiological supplementation with 1,25-(OH)2D3, suggests an autonomous role of the calcium ATPase activity for mediation of calcium transport in the duodenum in addition to the well-known mechanisms related to vitamin D and its metabolites.

scholarly journals The Role of the N-Domain in the ATPase Activity of the Mammalian AAA ATPase p97/VCP

2012 ◽  
Vol 287 (11) ◽  
pp. 8561-8570 ◽  
Author(s):  
Hajime Niwa ◽  
Caroline A. Ewens ◽  
Chun Tsang ◽  
Heidi O. Yeung ◽  
Xiaodong Zhang ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Aaa Atpase

scholarly journals Toward an understanding of the Cdc48/p97 ATPase

F1000Research ◽  
2017 ◽  
Vol 6 ◽  
pp. 1318 ◽  
Author(s):  
Nicholas Bodnar ◽  
Tom Rapoport
Keyword(s):  
Atp Hydrolysis ◽  
Critical Role ◽  
Ring Structure ◽  
Cellular Systems ◽  
Aaa Atpase ◽  
Double Ring ◽  
Terminal Domain ◽  
D2 Domain ◽  
Central Pore

A conserved AAA+ ATPase, called Cdc48 in yeast and p97 or VCP in metazoans, plays an essential role in many cellular processes by segregating polyubiquitinated proteins from complexes or membranes. For example, in endoplasmic reticulum (ER)-associated protein degradation (ERAD), Cdc48/p97 pulls polyubiquitinated, misfolded proteins out of the ER and transfers them to the proteasome. Cdc48/p97 consists of an N-terminal domain and two ATPase domains (D1 and D2). Six Cdc48 monomers form a double-ring structure surrounding a central pore. Cdc48/p97 cooperates with a number of different cofactors, which bind either to the N-terminal domain or to the C-terminal tail. The mechanism of Cdc48/p97 action is poorly understood, despite its critical role in many cellular systems. Recent in vitro experiments using yeast Cdc48 and its heterodimeric cofactor Ufd1/Npl4 (UN) have resulted in novel mechanistic insight. After interaction of the substrate-attached polyubiquitin chain with UN, Cdc48 uses ATP hydrolysis in the D2 domain to move the polypeptide through its central pore, thereby unfolding the substrate. ATP hydrolysis in the D1 domain is involved in substrate release from the Cdc48 complex, which requires the cooperation of the ATPase with a deubiquitinase (DUB). Surprisingly, the DUB does not completely remove all ubiquitin molecules; the remaining oligoubiquitin chain is also translocated through the pore. Cdc48 action bears similarities to the translocation mechanisms employed by bacterial AAA ATPases and the eukaryotic 19S subunit of the proteasome, but differs significantly from that of a related type II ATPase, the NEM-sensitive fusion protein (NSF). Many questions about Cdc48/p97 remain unanswered, including how it handles well-folded substrate proteins, how it passes substrates to the proteasome, and how various cofactors modify substrates and regulate its function.

scholarly journals The chaperone Hsp70 is a BH3 receptor activated by the pro-apoptotic Bim to stabilize anti-apoptotic clients

2020 ◽  
Vol 295 (37) ◽  
pp. 12900-12909
Author(s):  
Zongwei Guo ◽  
Ting Song ◽  
Ziqian Wang ◽  
Donghai Lin ◽  
Keke Cao ◽  
...  
Keyword(s):  
Atpase Activity ◽  
Cell Fate ◽  
Protein Misfolding ◽  
Structural Basis ◽  
Titration Calorimetry ◽  
Allosteric Site ◽  
Transverse Relaxation ◽  
Bh3 Domain

The chaperone heat shock protein 70 (Hsp70) is crucial for avoiding protein misfolding under stress, but is also up-regulated in many kinds of cancers, where its ability to buffer cellular stress prevents apoptosis. Previous research has suggested Hsp70 interacts with pro-apoptotic Bcl-2 family proteins, including Bim and Bax. However, a definitive demonstration of this interaction awaits, and insights into the structural basis and molecular mechanism remain unclear. Earlier studies have identified a Bcl-2 homology 3 (BH3) domain present in Bcl-2 family members that engages receptors to stimulate apoptosis. We now show that Hsp70 physically interacts with pro-apoptotic multidomain and BH3-only proteins via a BH3 domain, thereby serving as a novel BH3 receptor, using in vitro fluorescent polarization (FP), isothermal titration calorimetry (ITC), and cell-based co-immunoprecipitation (co-IP) experiments, 1H-15N-transverse relaxation optimized spectroscopy (TROSY-HSQC), trypsin proteolysis, ATPase activity, and denatured rhodanese aggregation measurements further demonstrated that BimBH3 binds to a novel allosteric site in the nucleotide-binding domain (NBD) of Hsp70, by which Bim acts as a positive co-chaperone to promote the ATPase activity and chaperone functions. A dual role of Hsp70's anti-apoptotic function was revealed that when it keeps Bim in check to inhibit apoptosis, it simultaneously stabilizes oncogenic clients including AKT and Raf-1 with the aid of Bim. Two faces of Bim in cell fate regulation were revealed that in opposite to its well-established pro-apoptotic activator role, Bim could help the folding of oncogenic proteins.

scholarly journals Transmembrane Polar Relay Drives the Allosteric Regulation for ABCG5/G8 Sterol Transporter

2020 ◽  
Vol 21 (22) ◽  
pp. 8747 ◽  
Author(s):  
Bala M. Xavier ◽  
Aiman A. Zein ◽  
Angelica Venes ◽  
Junmei Wang ◽  
Jyh-Yeuan Lee
Keyword(s):  
Atpase Activity ◽  
Signal Transmission ◽  
Transmembrane Domains ◽  
Water Soluble ◽  
Missense Mutations ◽  
Loss Of Function ◽  
Charged Amino Acids ◽  
Cholesteryl Hemisuccinate

The heterodimeric ATP-binding cassette (ABC) sterol transporter, ABCG5/G8, is responsible for the biliary and transintestinal secretion of cholesterol and dietary plant sterols. Missense mutations of ABCG5/G8 can cause sitosterolemia, a loss-of-function disorder characterized by plant sterol accumulation and premature atherosclerosis. A new molecular framework was recently established by a crystal structure of human ABCG5/G8 and reveals a network of polar and charged amino acids in the core of the transmembrane domains, namely, a polar relay. In this study, we utilize genetic variants to dissect the mechanistic role of this transmembrane polar relay in controlling ABCG5/G8 function. We demonstrated a sterol-coupled ATPase activity of ABCG5/G8 by cholesteryl hemisuccinate (CHS), a relatively water-soluble cholesterol memetic, and characterized CHS-coupled ATPase activity of three loss-of-function missense variants, R543S, E146Q, and A540F, which are respectively within, in contact with, and distant from the polar relay. The results established an in vitro phenotype of the loss-of-function and missense mutations of ABCG5/G8, showing significantly impaired ATPase activity and loss of energy sufficient to weaken the signal transmission from the transmembrane domains. Our data provide a biochemical evidence underlying the importance of the polar relay and its network in regulating the catalytic activity of ABCG5/G8 sterol transporter.

Restoring Oxygen Carrying Capacity of Sickle Erythrocytes with Nitric Oxide Donors.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3785-3785
Author(s):  
Borys Hrinczenko
Keyword(s):  
Nitric Oxide ◽  
Oxygen Affinity ◽  
Red Cell ◽  
No Donors ◽  
Sickle Erythrocytes ◽  
Low Levels ◽  
Pre Treatment ◽  
Normal Controls

Abstract Sickle cell anemia (SCA) is an inherited blood disorder of hemoglobin function. A genetic mutation results in the substitution of a valine for glutamic acid residue at position 6 of the beta-globin chain yielding the mutant hemoglobin S (HbS). HbS polymerizes within erythrocytes during deoxygenation resulting in altered affinity of oxygen binding. The slightly different P50 (PO2 at which Hb is half-saturated with oxygen) values of sickle erythrocytes obtained during either oxygenation or deoxygenation (hysteresis) demonstrate HbS polymerization induced inhibition of oxygen affinity. Nitric oxide (NO) has been found to be an important signaling molecule in the circulatory system. NO derivatives of Hb provide insights into the physiological role of Hb. NO can bind to Hb at either the heme moiety forming nitrosylhemoglobin (HbNO) or to the conserved beta-93 cysteine yielding S-nitrosohemoglobin (SNO-Hb). In deoxygenated venous blood NO preferentially binds to the hemes of Hb forming HbNO while in oxygenated arterial blood NO binds to the beta-93 cysteine residues forming SNO-Hb. Increased oxygen affinity is seen in both SNO-Hb (Bonaventura C, et al, 1999) and also with HbNO. Decreasing the HbS P50 inhibits intra-erythrocyte HbS polymerization that may be an effective strategy to treat SCA. Clinical trials of NO breathing effects on oxygen affinity are conflicting. One study found an increased oxygen affinity of blood from SCA patients breathing 80 ppm NO with no effect seen in normal controls (Head A, et al, 1997). Another study found that levels of NO bound to Hb are too low to affect overall oxygen affinity (Gladwin M, et al, 1999). The purpose of this in vitro study was to determine the oxygen affinity of deoxygenated sickle erythrocytes pre-treated with exogenous NO donors. Blood from SCA (HbSS) and normal controls (HbAA) were collected and suspended in PBS buffer and deoxygenated with argon gas. The Hb concentration of each sample was calculated and then was either left untreated (control) or treated with varying concentrations of NO donors. The NO donors included: 2-(N, N-diethylamino)-diazenolate-2-oxide (DEANO), S-nitroso-N-acetylpenicillamine (SNAP), sodium nitroprusside (SNP), an aqueous solution of NO, and sodium trioxodinitrate (Angeli’s salt, AS). Methemoglobin and protein degradation were negligible. Samples were then transferred via airtight syringes into a stirred and temperature controlled (37°C) chamber of PBS solution at ambient oxygen pressure fitted with a very sensitive oxygen electrode. Oxygen levels were measured in real time. The amount of oxygen extracted from the PBS medium followed first order kinetics. Studies with HbSS red cell suspensions showed that the largest increment in oxygen extraction from the medium was obtained with DEANO pre-treatment. Calculations indicated that low levels of NO treatment, at approximately a 1:1000 ratio of [NO]/[heme], yielded the largest oxygen consumption. The effects of pre-treatment with the other NO donors on sickle erythrocytes (HbSS) were not as pronounced. DEANO is an NO donor yielding a “pure” NO radical as opposed to other redox forms. Similar studies with HbAA and HbSC did not show increases in oxygen extraction. Taken together the data suggest that low levels of NO perturb the quaternary structure of intraerythrocyte HbS polymer allowing depolymerization and increased oxygen affinity. The hope is that these in vitro studies will better characterize the role of NO in its interactions with Hb and the red cell and to use this knowledge for potential therapies in diseases such as SCA.

scholarly journals GCUNC-45 Is a Novel Regulator for the Progesterone Receptor/hsp90 Chaperoning Pathway

2006 ◽  
Vol 26 (5) ◽  
pp. 1722-1730 ◽  
Author(s):  
Ahmed Chadli ◽  
J. Dinny Graham ◽  
M. Greg Abel ◽  
Twila A. Jackson ◽  
David F. Gordon ◽  
...  
Keyword(s):  
Progesterone Receptor ◽  
Atpase Activity ◽  
Binding Site ◽  
Signaling Pathway ◽  
Regulatory Proteins ◽  
N Terminus ◽  
Positive Factor

ABSTRACT The hsp90 chaperoning pathway is a multiprotein system that is required for the production or activation of many cell regulatory proteins, including the progesterone receptor (PR). We report here the identity of GCUNC-45 as a novel modulator of PR chaperoning by hsp90. GCUNC-45, previously implicated in the activities of myosins, can interact in vivo and in vitro with both PR-A and PR-B and with hsp90. Overexpression and knockdown experiments show GCUNC-45 to be a positive factor in promoting PR function in the cell. GCUNC-45 binds to the ATP-binding domain of hsp90 to prevent the activation of its ATPase activity by the cochaperone Aha1. This effect limits PR chaperoning by hsp90, but this can be reversed by FKBP52, a cochaperone that is thought to act later in the pathway. These findings reveal a new cochaperone binding site near the N terminus of hsp90, add insight on the role of FKBP52, and identify GCUNC-45 as a novel regulator of the PR signaling pathway.

Endotoxin and myocardial failure: role of the myofibril and venous return

1978 ◽  
Vol 235 (2) ◽  
pp. H150-H156 ◽  
Author(s):  
F. D. Bruni ◽  
P. Komwatana ◽  
M. E. Soulsby ◽  
M. L. Hess
Keyword(s):  
Atpase Activity ◽  
Venous Return ◽  
Normal Activity ◽  
Left Ventricular ◽  
Myofibrillar Atpase ◽  
Myocardial Failure ◽  
Myofibrillar Atpase Activity ◽  
Myofibril Preparation

The effects of gramnegative endotoxin-induced myocardial failure in the pentobarbital-anesthetized dog were examined by monitoring its influence on cardiac myofibrillar ATPase activity. Myofibrils were isolated from endo- and epicardial portions of the left ventricular wall. ATPase activities were determined in animals treated with 4 mg/kg endotoxin and monitored 5 h, in animals monitored for 5 h without endotoxin (controls), and in animals implanted with a unilateral femoral shunt and given endotoxin. No differences were seen in the activities between the endo- and epicardial portions of any preparation. Activity was significantly depressed in endotoxemic animals. Increasing venous return by 313 +/- 71 ml/min significantly increased coronary flow by reducing coronary vascular resistance and prevented any observed depression of myofibrillar ATPase activity. In in vitro studies, adding endotoxin directly to a myofibril preparation did not modify normal activity. It appears that the mechanical and myofibrillar dysfunctions are due to the action of endotoxin at sites not associated with the actomyosin ATPase, but may be due to the production of an intermediary agent in concert with a decreased venous return.

scholarly journals VCP/p97 controls signals of the ERK1/2 pathway transmitted via the Shoc2 scaffolding complex: novel insights into IBMPFD pathology

2019 ◽  
Vol 30 (14) ◽  
pp. 1655-1663 ◽  
Author(s):  
HyeIn Jang ◽  
Eun Ryoung Jang ◽  
Patricia G. Wilson ◽  
Daniel Anderson ◽  
Emilia Galperin
Keyword(s):  
Atpase Activity ◽  
Frontotemporal Dementia ◽  
Inclusion Body ◽  
Critical Role ◽  
Germline Mutations ◽  
Aaa Atpase ◽  
Ubiquitin System ◽  
Signaling Axis ◽  
Mechanistic Basis

Valosin-containing protein (VCP), also named p97, is an essential hexameric AAA+ ATPase with diverse functions in the ubiquitin system. Here we demonstrate that VCP is critical in controlling signals transmitted via the essential Shoc2-ERK1/2 signaling axis. The ATPase activity of VCP modulates the stoichiometry of HUWE1 in the Shoc2 complex as well as HUWE1-mediated allosteric ubiquitination of the Shoc2 scaffold and the RAF-1 kinase. Abrogated ATPase activity leads to augmented ubiquitination of Shoc2/RAF-1 and altered phosphorylation of RAF-1. We found that in fibroblasts from patients with inclusion body myopathy with Paget’s disease of bone and frontotemporal dementia (IBMPFD) that harbor germline mutations in VCP, the levels of Shoc2 ubiquitination and ERK1/2 phosphorylation are imbalanced. This study provides a mechanistic basis for the critical role of VCP in the regulation of the ERK1/2 pathway and reveals a previously unrecognized function of the ERK1/2 pathway in the pathogenesis of IBMPFD.

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