Understanding Carbamoyl Phosphate Synthetase Deficiency: Impact of Clinical Mutations on Enzyme Functionality

Yefimenko, Igor; Fresquet, Vicente; Marco-Marı́n, Clara; Rubio, Vicente; Cervera, Javier

doi:10.1016/j.jmb.2005.03.078

Cited by 36 publications

(40 citation statements)

References 63 publications

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“…Since defects in CPS1 are known to trigger hyper-ammonemia in humans (Yefimenko et al, 2005), we predicted that the deficiency in SIRT5 KO mice after 48-hour fasting might result in hyper-ammonemia. Thus, we subjected wild type and SIRT5 KO mice to 48 hours fasting and then determined their blood ammonia levels.…”

Section: Resultsmentioning

confidence: 99%

“…Here we show that this sirtuin is a mitochondrial matrix NAD-dependent deacetylase that is specific for carbamoyl phosphate synthetase 1 (CPS1), the committed and regulated enzyme of the urea cycle (Haussinger, 1990; Meijer et al, 1990). CPS1 is critical in the detoxification of excess ammonia, and patients with CPS1 deficiency suffer from hyper-ammonemia, which can lead to mental retardation and death (Yefimenko et al, 2005). In normal individuals, excess ammonia is produced when amino acids are used as energy sources, for example during fasting (Meijer et al, 1990; Morris, 2002; Schimke, 1962b).…”

Section: Introductionmentioning

confidence: 99%

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SIRT5 Deacetylates Carbamoyl Phosphate Synthetase 1 and Regulates the Urea Cycle

Nakagawa

Lomb

Haigis

et al. 2009

Cell

696

684

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Summary Sirtuins are NAD-dependent protein deacetylases that connect metabolism and aging. In mammals, there are seven sirtuins (SIRT1-7), three of which are associated with mitochondria. Here we show that SIRT5 localizes in the mitochondrial matrix and interacts with carbamoyl phosphate synthetase 1 (CPS1), an enzyme, catalyzing the initial step of the urea cycle for ammonia detoxification and disposal. SIRT5 deacetylates CPS1 and up-regulates its activity. During fasting, NAD in liver mitochondria increases, thereby triggering SIRT5 deacetylation of CPS1 and adaptation to the increase in amino acid catabolism. Indeed, SIRT5 KO mice fail to up-regulate CPS1 activity and show elevated blood ammonia during fasting. Similar effects occur during long-term calorie restriction or a high protein diet. These findings demonstrate SIRT5 plays a pivotal role in ammonia detoxification and disposal by activating CPS1.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

SIRT5 Deacetylates Carbamoyl Phosphate Synthetase 1 and Regulates the Urea Cycle

Nakagawa

Lomb

Haigis

et al. 2009

Cell

696

684

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“…We also document for some mutations and propose for other mutations that they have effects of greater or lower magnitude on the V max of the enzyme. This effect could be due to gross defects on domain architecture, that, for example, could block the conduit of the activating allosteric NAG signal, or the tunnel [27] through which intermediates must flow between both phosphorylation centers; or it could derive from more subtle changes such as the hampering of the concerted opening [56,57] of the B subdomains of both phosphorylation domains to allow product release. Indeed, mutations in the UFSD could be in the signaling path between both phosphorylation centers since the UFSD contacts the B domain of the carbamate phosphorylation domain, which is believed to trigger the concerted opening [57], and it also contacts the active site of the bicarbonate phosphorylation domain, which is to be opened (Fig.…”

Section: Discussionmentioning

confidence: 99%

Understanding carbamoyl phosphate synthetase (CPS1) deficiency by using the recombinantly purified human enzyme: Effects of CPS1 mutations that concentrate in a central domain of unknown function

Dı́ez-Fernández

Cervera

et al. 2014

Molecular Genetics and Metabolism

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Carbamoyl phosphate synthetase 1 deficiency (CPS1D) is an inborn error of the urea cycle that is due to mutations in the CPS1 gene. In the first large repertory of mutations found in CPS1D, a small CPS1 domain of unknown function (called the UFSD) was found to host missense changes with high frequency, despite the fact that this domain does not host substrate-binding or catalytic machinery. We investigate here by in vitro expression studies using baculovirus/insect cells the reasons for the prominence of the UFSD in CPS1D, as well as the disease-causing roles and pathogenic mechanisms of the mutations affecting this domain. All but three of the 18 missense changes found thus far mapping in this domain in CPS1D patients drastically decreased the yield of pure CPS1, mainly because of decreased enzyme solubility, strongly suggesting misfolding as a major determinant of the mutations negative effects. In addition, the majority of the mutations also decreased from modestly to very drastically the specific activity of the fraction of the enzyme that remained soluble and that could be purified, apparently because they decreased V max . Substantial although not dramatic increases in K m values for the substrates or for N-acetyl-L-glutamate were observed for only five mutations.Similarly, important thermal stability decreases were observed for three mutations. The results indicate a disease-causing role for all the mutations, due in most cases to the combined effects of the low enzyme level and the decreased activity. Our data strongly support the value of the present expression system for ascertaining the disease-causing potential of CPS1 mutations, provided that the CPS1 yield is monitored. The observed effects of the mutations have been rationalized on the basis of an existing structural model of CPS1. This model shows that the UFSD, which is in the middle of the 1462-residue multidomain CPS1 protein, plays a key integrating role for creating the CPS1 multidomain architecture leading us to propose here a denomination of "Integrating 3 Domain" for this CPS1 region. The majority of these 18 mutations distort the interaction of this domain with other CPS1 domains, in many cases by causing improper folding of structural elements of the Integrating Domain that play key roles in these interactions.

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“…Although no prevalent ''common'' mutation was identified, some of the mutations were shared by more than one family, probably reflecting relatively common mutations among Japanese. Figure 1 describes the position of these mutations in relation to previously identified functional domains of the CPS1 molecule (Yefimenko et al 2005). All but two missense mutations (G79E and Y212N) were Aoshima et al 2001b clustered around the two phosphorylation domains, while the nonsense and in/del mutations are scattered throughout the gene.…”

Section: Dna Analysismentioning

confidence: 99%

Molecular and clinical analyses of Japanese patients with carbamoylphosphate synthetase 1 (CPS1) deficiency

et al. 2007

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Carbamoylphosphate synthetase I deficiency (CPS1D) is a urea-cycle disorder characterized by episodes of life-threatening hyperammonemia. Correct diagnosis is crucial for patient management, but is difficult to make from clinical presentation and conventional laboratory tests alone. Enzymatic or genetic diagnoses have also been hampered by difficult access to the appropriate organ and the large size of the gene (38 exons). In this study, in order to address this diagnostic dilemma, we performed the largest 349-354 DOI 10.1007/s10038-007-0122-9 mutational and clinical analyses of this disorder to date in Japan. Mutations in CPS1 were identified in 16 of 18 patients with a clinical diagnosis of CPS1D. In total, 25 different mutations were identified, of which 19 were novel. Interestingly, in contrast to previous reports suggesting an extremely diverse mutational spectrum, 31.8% of the mutations identified in Japanese were common to more than one family. We also identified two common polymorphisms that might be useful for simple linkage analysis in prenatal diagnosis. The accumulated clinical data will also help to reveal the clinical presentation of this rare disorder in Japan.

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Understanding Carbamoyl Phosphate Synthetase Deficiency: Impact of Clinical Mutations on Enzyme Functionality

Cited by 36 publications

References 63 publications

SIRT5 Deacetylates Carbamoyl Phosphate Synthetase 1 and Regulates the Urea Cycle

SIRT5 Deacetylates Carbamoyl Phosphate Synthetase 1 and Regulates the Urea Cycle

Understanding carbamoyl phosphate synthetase (CPS1) deficiency by using the recombinantly purified human enzyme: Effects of CPS1 mutations that concentrate in a central domain of unknown function

Molecular and clinical analyses of Japanese patients with carbamoylphosphate synthetase 1 (CPS1) deficiency

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