1
|
Brüser A, Kirchberger J, Schöneberg T. Altered allosteric regulation of muscle 6-phosphofructokinase causes Tarui disease. Biochem Biophys Res Commun 2012; 427:133-7. [PMID: 22995305 DOI: 10.1016/j.bbrc.2012.09.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 09/06/2012] [Indexed: 11/18/2022]
Abstract
Tarui disease is a glycogen storage disease (GSD VII) and characterized by exercise intolerance with muscle weakness and cramping, mild myopathy, myoglobinuria and compensated hemolysis. It is caused by mutations in the muscle 6-phosphofructokinase (Pfk). Pfk is an oligomeric, allosteric enzyme which catalyzes one of the rate-limiting steps of the glycolysis: the phosphorylation of fructose 6-phosphate at position 1. Pfk activity is modulated by a number of regulators including adenine nucleotides. Recent crystal structures from eukaryotic Pfk displayed several allosteric adenine nucleotide binding sites. Functional studies revealed a reciprocal linkage between the activating and inhibitory allosteric binding sites. Herein, we showed that Asp(543)Ala, a naturally occurring disease-causing mutation in the activating binding site, causes an increased efficacy of ATP at the inhibitory allosteric binding site. The reciprocal linkage between the activating and inhibitory binding sites leads to reduced enzyme activity and therefore to the clinical phenotype. Pharmacological blockage of the inhibitory allosteric binding site or highly efficient ligands for the activating allosteric binding site may be of therapeutic relevance for patients with Tarui disease.
Collapse
Affiliation(s)
- Antje Brüser
- Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | | | | |
Collapse
|
2
|
Abstract
The authors' impression is that the CBC provides much more information than is routinely used. When anemia is present, the CBC contains considerable information regarding its cause, which can assist in formulating a differential diagnosis and directing further evaluation. White blood cell and platelet count levels may similarly direct practitioners to consider or dismiss underlying conditions. This article assists the pediatrician in optimizing use of this familiar diagnostic tool.
Collapse
Affiliation(s)
- M C Walters
- Department of Pediatrics, University of Washington School of Medicine, Seattle, USA
| | | |
Collapse
|
3
|
Vaisanen PA, Reddy GR, Sharma PM, Kohani R, Johnson JL, Raney AK, Babior BM, McLachlan A. Cloning and characterization of the human muscle phosphofructokinase gene. DNA Cell Biol 1992; 11:461-70. [PMID: 1388024 DOI: 10.1089/dna.1992.11.461] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
A 35-kbp region of genomic DNA encoding the human muscle phosphofructokinase (HPFK-M) gene including all of the coding exons (1-22) plus 2.2-kbp of 5'-flanking sequence has been cloned. The exon boundaries are the same as has been observed for the rabbit muscle phosphofructokinase (RPFK-M), the human liver phosphofructokinase (HPFK-L), and the mouse liver phosphofructokinase (MPFK-L) genes. Characterization of the structure of the HPFK-M gene and its transcript in Epstein-Barr virus transformed B-cell lines derived from patients with glycogen storage disease type VII (GSDVII or Tarui's disease) demonstrated that this single-copy gene encodes a normal sized 3.0-kb transcript in the four cases examined. This suggests the lesion in these cases represents either a point mutation or possibly a small insertion or deletion resulting in the synthesis of a defective HPFK-M protein. Analysis of the 5'-flanking region demonstrated the presence of a functional promoter located within 114 nucleotides of a proposed transcription initiation site. This promoter was active in the human cervical carcinoma cell line, HeLa S3, the dedifferentiated human hepatoma cell line, HepG2.1, and the mouse myoblast cell line, C2C12, suggesting this promoter has a broad cell-type specificity. In addition, from the known HPFK-M cDNA sequences, this observation indicates that the HPFK-M gene has a second promoter located upstream from the genomic region isolated in this study.
Collapse
Affiliation(s)
- P A Vaisanen
- Department of Molecular and Experimental Medicine, Scripps Research Institute, La Jolla, CA 92037
| | | | | | | | | | | | | | | |
Collapse
|
4
|
Jacobs AE, Oosterhof A, Benders AA, Veerkamp JH. Expression of different isoenzymes of adenylate deaminase in cultured human muscle cells. Relation to myoadenylate deaminase deficiency. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1139:91-5. [PMID: 1610923 DOI: 10.1016/0925-4439(92)90087-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Adenylate deaminase activity was determined in cultured muscle cells of different maturation grades and muscle biopsies from normal subjects and four patients with a primary myoadenylate deaminase (MAD) deficiency. Adenylate deaminase activity was much lower in cultured human muscle cells than in normal muscle. The activity increased with maturation. The ratio of activities measured at 5 and 2 mM AMP decreased in the order: immature muscle cells greater than more mature muscle cells greater than muscle. Adenylate deaminase activity was detectable in muscle cell cultures of MAD-deficient patients. However, both at 2 and 5 mM AMP this activity was significantly lower than in cultured cells with the same high maturation grade obtained from control subjects, whereas the ratio between the activities at 5 and 2 mM AMP was higher. The observations indicate that transition from a fetal to an adult muscle isoenzyme of adenylate deaminase takes place in human cultured muscle cells during maturation. In cultures obtained from MAD-deficient patients this transition does not occur and only the fetal isoenzyme is present.
Collapse
Affiliation(s)
- A E Jacobs
- Department of Biochemistry, University of Nijmegen, Netherlands
| | | | | | | |
Collapse
|
5
|
Mhaskar Y, Harvey JW, Dunaway GA. Developmental changes of 6-phosphofructo-1-kinase subunit levels in erythrocytes from normal dogs and dogs affected by glycogen storage disease type VII. COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY. B, COMPARATIVE BIOCHEMISTRY 1992; 101:303-7. [PMID: 1533828 DOI: 10.1016/0305-0491(92)90003-a] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
1. The subunit proportions (L:M:C) of the PFK isozymes from normal adult erythrocytes were 2:86:12. Affected adult erythrocyte 6-phosphofructo-1-kinase (PFK) isozymes contained normal L-type (31%) and C-type (61%) subunits as well as a small amount (8%) of truncated M-type subunit. 2. When measured within 24 hr of birth, both normal and affected dog erythrocytes contained high PFK activities due to elevated levels of the L-type subunit. As the dogs matured, PFK activity decreased due to a greater than 99% loss of the L-type subunit. 3. By 2 weeks of age, the M-type and C-type subunits in normal dog PFK isozymes increased several-fold and attained near adult levels. 4. During post-natal development, the L-type subunit from affected dog erythrocytes decreased more rapidly than from normal dog erythrocytes; but it was maintained at a higher level in the affected adult erythrocytes. Also, in the affected dog erythrocytes, truncated M-type subunits were detected; and the initially high levels of the C-type subunit decreased approximately 50% after 4 weeks.
Collapse
Affiliation(s)
- Y Mhaskar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield 62794-9230
| | | | | |
Collapse
|
6
|
|
7
|
Jacobs AE, Benders AA, Oosterhof A, Veerkamp JH, van Mier P, Wevers RA, Joosten EM. The calcium homeostasis and the membrane potential of cultured muscle cells from patients with myotonic dystrophy. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1096:14-9. [PMID: 2176547 DOI: 10.1016/0925-4439(90)90006-b] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Using the fluorescence indicator, quin2, we compared the cytoplasmic Ca2+ concentration ([Ca2+]i) of cultured myotubes obtained from control subjects and myotonic dystrophy (MyD) patients. In Ca2(+)-free buffer the [Ca2+]i of the cultured MyD muscle cells was not significantly different from that of the control cells. In the presence of 1 mM external Ca2+ the cultured MyD muscle cells showed a significantly higher [Ca2+]i, which was due to the influx of Ca2+ through voltage-operated nifedipine-sensitive Ca2+ channels. In the presence of external Ca2+, MyD myotubes did not respond to acetylcholine, whereas control myotubes showed a transient increase in [Ca2+]i after addition of acetylcholine. This increase was inhibited by the addition of nifedipine. The differences in Ca2(+)-homeostasis between cultured MyD muscle cells and control cells were not due to differences in the resting membrane potential or the inability of the MyD cells to depolarize as a response to acetylcholine. Therefore, cultured MyD muscle cells exhibit altered nifedipine-sensitive voltage-operated channels which are active under conditions in which they are normally present in the inactive state, and which are unable to respond to depolarization caused by acetylcholine.
Collapse
Affiliation(s)
- A E Jacobs
- Department of Biochemistry, University of Nijmegen, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
8
|
|
9
|
Vora S, DiMauro S, Spear D, Harker D, Danon MJ. Characterization of the enzymatic defect in late-onset muscle phosphofructokinase deficiency. New subtype of glycogen storage disease type VII. J Clin Invest 1987; 80:1479-85. [PMID: 2960695 PMCID: PMC442407 DOI: 10.1172/jci113229] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Human phosphofructokinase (PFK) exists in tetrameric isozymic forms, at least in vitro. Muscle and liver contain homotetramers M4 and L4, respectively, whereas red cells contain five isozymes composed of M (muscle) and L (liver) type subunits, i.e., M4, M3L, M2L2, and ML3, and L4. Homozygous deficiency of muscle PFK results in the classic glycogen storage disease type VII characterized by exertional myopathy and hemolytic syndrome beginning in early childhood. The genetic lesion results in a total and partial loss of muscle and red cell PFK, respectively. Characteristically, the residual red cell PFK from the patients consists of isolated L4 isozyme; the M-containing hybrid isozymes are completely absent. In this study, we investigated an 80-yr-old man who presented with a 10-yr history of progressive weakness of the lower limbs as the only symptom. The residual red cell PFK showed the presence of a few M-containing isozymes in addition to the predominant L4 species, indicating that the genetic lesion is a "leaky" mutation of the gene coding for the M subunit. The presence of a small amount of enzyme activity in the muscle may account for the atypical myopathy in this patient.
Collapse
Affiliation(s)
- S Vora
- Department of Basic and Clinical Research, Scripps Clinic and Research Foundation, La Jolla, California 92037
| | | | | | | | | |
Collapse
|
10
|
Abstract
A cDNA for human muscle 6-phosphofructokinase (EC.2.7.1.11) has been isolated from a human fibroblast cDNA library made using the Okayama-Berg procedure. The cDNA isolated as a Bam H1 fragment of the pcD recombinant, pO4, is approximately 2000 bp in length. It represents approximately 1350 bp of the C-terminus coding sequence of the enzyme, approximately 500 bp of the 3'-untranslated region and approximately 150 bp of the vector sequences. The identity of the pO4 cDNA was established by the observation of a high degree of homology (approximately 95%) between the deduced amino acid sequence with the published protein sequence of rabbit muscle 6-phosphofructokinase, and the assignment of the sequence to human chromosome 1 (the known location of PFKM) by using somatic cell hybrids. Based on immunochemical evidence, we had previously predicted not only a remarkable structural conservation of the vertebrate muscle PFK, but also partial structural identity among all three vertebrate PFK isozymes. The pO4 cDNA is, therefore, expected to permit isolation of cDNAs for muscle and non-muscle PFKs from a wide variety of vertebrate species.
Collapse
|
11
|
Sims NR, Blass JP. Phosphofructokinase activity in fibroblasts from patients with Alzheimer's disease and age- and sex-matched controls. Metab Brain Dis 1986; 1:83-90. [PMID: 2977422 DOI: 10.1007/bf00998479] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The activity of the enzyme phosphofructokinase (PFK) was comparable in cultured skin fibroblasts from eight patients with Alzheimer's disease and eight age- and sex-matched controls. Mean activities were similar in the two groups whether measured under nonallosteric conditions at pH 8.0 or under allosteric conditions at pH 7.0, in the presence of 0.1 or 1 mM ATP. Activities of PFK in Alzheimer's disease and control cells also showed a similar temperature dependence and similar isozyme patterns on column chromatography. These results argue against the existence of significant structural variations of PFK in Alzheimer's disease.
Collapse
Affiliation(s)
- N R Sims
- Altschul Laboratory for Dementia Research, Cornell University Medical College, White Plains, New York 10605
| | | |
Collapse
|
12
|
Miwa S, Fujii H. Molecular aspects of erythroenzymopathies associated with hereditary hemolytic anemia. Am J Hematol 1985; 19:293-305. [PMID: 2990202 DOI: 10.1002/ajh.2830190313] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Since the discovery of glucose 6-phosphate dehydrogenase (G6PD) and of pyruvate kinase deficiencies, erythroenzymopathies associated with hereditary hemolytic anemia have been extensively investigated. Kinetic and electrophoretic studies have shown that most, if not all, erythroenzymopathies are caused by the production of a mutant enzyme. Except for a few enzymes that are abundant in blood and tissues, it is difficult to obtain enough sample to study the functional and structural abnormalities of mutant enzymes associated with genetic disorders in man. The primary structures of only two normal red cell enzymes which can cause hereditary hemolytic anemia, phosphoglycerate kinase (PGK) and adenylate kinase, have been determined. Single amino acid substitutions of PGK variants have been found, and the identification of the exact molecular abnormalities of such variants has helped us to understand the accompanying functional abnormality. Gene cloning makes possible the identification of the DNA sequence that codes for enzyme proteins. Recently, human complementary DNA (cDNA) for aldolase, PGK, G6PD, and adenosine deaminase (ADA) have been isolated, and the nucleotide sequences for PGK and ADA determined. In the near future, human cDNA sequencing should permit identification of the gene alteration that gives rise to the mutant enzymes.
Collapse
|
13
|
Abstract
Hybridoma antibodies are powerful tools. Their impact is already apparent in many areas of basic and applied research. In contrast, their impact is just beginning to be felt in enzymology. The existing literature on monoclonal antibodies to enzymes and isozymes, reviewed in this article, is as yet largely descriptive. However, the potential applications discussed herein promise to revolutionize existing strategies of unraveling the basic biochemistry, immunochemistry, and developmental, somatic cell, and molecular genetics of enzymes and isozymes. At a clinical level, monoclonal antibodies to enzymes promise to radically improve the current modalities of diagnosis and therapy in clinical enzymology and oncology. It is becoming increasingly apparent that the future applications of hybridoma antibodies to enzymes and isozymes appear to be limited only by our imagination.
Collapse
|
14
|
Zuurveld JG, Oosterhof A, Veerkamp JH, van Moerkerk HT. Oxidative metabolism of cultured human skeletal muscle cells in comparison with biopsy material. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 844:1-8. [PMID: 3967049 DOI: 10.1016/0167-4889(85)90226-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Human muscle cell cultures were examined for capacities to oxidize several substrates, and for activities of some enzymes related to intermediate metabolism. The results indicate that mitochondrial activities attained appreciable degrees of maturity. The specific activity of creatine kinase increased during myoblast fusion. In contrast, parameters of oxidative metabolism (palmitate and pyruvate oxidation, and cytochrome c oxidase and citrate synthase) did not significantly change throughout myogenesis and thereafter. In differentiated cells (myotubes) the oxidation capacities were pyruvate greater than 2-oxoglutarate greater than malate (+ acetylcarnitine) greater than malate (+ pyruvate), as in muscle biopsies. With regard to protein the cultured human muscle cells showed higher activities than the original biopsies (= 100%) with respect to citrate synthase (179%), but lower values for cytochrome c oxidase (50%) and creatine kinase (7%). Palmitate oxidation capacities were the same in both systems. The presence of antimycin and rotenon inhibited to a comparable extent the palmitate oxidation in cultured muscle and biopsies.
Collapse
|
15
|
Human Myopathies in Muscle Culture: Morphological, Cytochemical, and Biochemical Studies. ACTA ACUST UNITED AC 1985. [DOI: 10.1016/b978-0-12-007904-9.50008-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
|
16
|
Vora S, Davidson M, Seaman C, Miranda AF, Noble NA, Tanaka KR, Frenkel EP, Dimauro S. Heterogeneity of the molecular lesions in inherited phosphofructokinase deficiency. J Clin Invest 1983; 72:1995-2006. [PMID: 6227635 PMCID: PMC437040 DOI: 10.1172/jci111164] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Human phosphofructokinase (PFK; EC 2.7.1.11) exists in tetrameric isozymic forms. Muscle and liver contain the homotetramers M4 and L4, whereas erythrocytes contain five isozymes composed of M (muscle) and L (liver) subunits, i.e., M4, M3L, M2L2, ML3, and L4. Inherited defects of erythrocyte PFK are usually partial and are described in association with heterogeneous clinical syndromes. To define the molecular basis and pathogenesis of this enzymopathy, we investigated four unrelated individuals manifesting myopathy and hemolysis (glycogenosis type VII), isolated hemolysis, or no symptoms at all. The three symptomatic patients showed high-normal hemoglobin levels, despite hemolysis and early-onset hyperuricemia. They showed total lack of muscle-type PFK and suffered from exertional myopathy of varying severity. In the erythrocytes, a metabolic crossover was evident at the PFK step: the levels of hexose monophosphates were elevated and those of 2,3-diphosphoglycerate (2,3-DPG) were depressed, causing strikingly increased hemoglobin-oxygen affinity. In all cases, the residual erythrocyte PFK consisted exclusively of L4 isozyme, indicating homozygosity for the deficiency of the catalytically active M subunit. However, presence of immunoreactive M subunit was shown in cultured fibroblasts by indirect immunofluorescence with monoclonal anti-M antibody. The fourth individual was completely asymptomatic, had normal erythrocyte metabolism, and had no evidence of hemolysis. His residual erythrocyte PFK showed a striking decrease of the L4, ML3, and M2L2 isozymes, secondary to a mutant unstable L subunit. Identical alterations of erythrocyte PFK were found in his asymptomatic son, indicating heterozygosity for the mutant unstable L subunit in this kindred. These studies show that, except for the varying severity of the myopathic symptoms, glycogenosis type VII has highly uniform clinical and biochemical features and results from homozygosity for mutant inactive M subunit(s). The absence of anemia despite hemolysis may be explained by the low 2,3-DPG levels. The hyperuricemia may result from hyperactivity of the hexose monophosphate shunt. In contrast, the clinically silent carrier state results from heterozygosity for mutant M or L subunit. Of the two, the M subunit appears to be more critical for adequate glycolytic flux in the erythrocyte, since its absence is correlated with hemolysis.
Collapse
|
17
|
Davidson M, Collins M, Byrne J, Vora S. Alterations in phosphofructokinase isoenzymes during early human development. Establishment of adult organ-specific patterns. Biochem J 1983; 214:703-10. [PMID: 6226285 PMCID: PMC1152306 DOI: 10.1042/bj2140703] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Human 6-phosphofructokinase (EC 2.7.1.11) exists in tetrameric isoenzymic forms composed of muscle (M), liver (L) and platelet (P) subunits, which are under separate genetic control. In the adult, the proportion of these subunits in different organs reflects the relative activity of glycolysis versus gluconeogenesis. To elucidate the developmental basis for the observed distribution, we investigated the isoenzymic transitions of phosphofructokinase in human foetuses (12-40 weeks' gestation) by using high-resolution chromatography and monoclonal antibodies. We studied skeletal muscle, heart, liver and brain because these organs show very different glycolytic fluxes and isoenzymic patterns in adult individuals. Our results demonstrate that there is no unique 'foetal' form of phosphofructokinase in humans, but all three loci are variably expressed in all foetal organs during early gestation. As development proceeds, muscle and liver isoenzyme patterns show dramatic changes, with disappearance of P and L subunits in muscle and transient reappearance of M and P subunits in liver; in contrast, phosphofructokinase isoenzymes change little in brain and heart. Most changes occur at mid-gestation and near term, and adult isoenzyme patterns are expressed at birth, indicating that organ differentiation is complete. These studies show that phosphofructokinase undergoes changes of isoenzyme patterns similar to, but not identical with, those of other multilocus isoenzyme systems of glycolysis. The observed changes probably reflect changing patterns of gene expression, with repression of some loci and activation of others.
Collapse
|