| 1. |
- Filling, Charlotta, et al.
(författare)
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Role of short-chain hydroxyacyl CoA dehydrogenases in SCHAD deficiency.
- 2008
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Ingår i: Biochemical and Biophysical Research Communications - BBRC. - : Elsevier BV. - 0006-291X .- 1090-2104. ; 368:1
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Tidskriftsartikel (refereegranskat)abstract
- Short-chain hydroxyacyl CoA dehydrogenase deficiency is an ill-defined, severe pediatric disorder of mitochondrial fatty acid beta-oxidation of short-chain hydroxyacyl CoAs. To understand the relative contributions of the two known short-chain hydroxyacyl CoA dehydrogenases (HADH) tissue biopsies of six distinct family individuals were analyzed and kinetic parameters were compared. Steady-state kinetic constants for HADH 1 and HADH 2 suggest that type 1 is the major enzyme involved in mitochondrial beta-oxidation of short-chain hydroxyacyl-CoAs. Two patients are heterozygous carriers of a HADH 1 polymorphism, whereas no mutation is detected in the HADH 2 gene of all patients. The data suggest that protein interactions rather than HADH mutations are responsible for the disease phenotype. Pull-down experiments of recombinant HADH 1 and 2 with human mitochondrial extracts reveal two proteins interacting with HADH 1, one of which was identified as glutamate dehydrogenase. This association provides a possible link between fatty acid metabolism and the hyperinsulinism/hyperammonia syndrome.
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| 2. |
- Hult, Malin, et al.
(författare)
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Short-term glucocorticoid treatment increases insulin secretion in islets derived from lean mice through multiple pathways and mechanisms
- 2009
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Ingår i: Molecular and Cellular Endocrinology. - : Elsevier BV. - 0303-7207 .- 1872-8057. ; 301:1-2, s. 109-116
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Tidskriftsartikel (refereegranskat)abstract
- Chronic exposure to elevated levels of glucocorticoids leads to metabolic dysfunctions with hyperglycemia and insulin resistance. Long-term treatment with glucocorticoids induces severe impairment of glucose-stimulated insulin secretion. We analyzed the effects of short-, and medium-term (2-120h) treatment with 50-200nM glucocorticoids on primary pancreatic islet cultures derived from lean C57BL/6J mice. In contrast to animal models of insulin resistance, beta-cells from lean mice respond with an increased glucose-stimulated insulin secretion, with a peak effect around 18-24h of treatment. Analyses of the insulin secretion response reveal that early and late phase responses are dissociated upon glucocorticoid treatment. Whereas late phase responses return to basal levels after long treatment, early phase responses remain increased over several days. Increased insulin secretion is also obtained by incubation with the inactive glucocorticoid dehydrocorticosterone, pointing to an important role of the enzyme 11beta-hydroxysteroid dehydrogenase type 1 in mediating glucocorticoid effects in beta-cells. Transcript profiling revealed differential regulation of genes involved in mediation of signal transduction, insulin secretion, stress and inflammatory responses. The results show that short- to medium-term glucocorticoid treatment of pancreatic islets derived from lean mice leads to an increased insulin release and may constitute an important parameter in changing towards a pro-diabetic phenotype.
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| 3. |
- Jornvall, Hans, et al.
(författare)
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Superfamilies SDR and MDR: From early ancestry to present forms. Emergence of three lines, a Zn-metalloenzyme, and distinct variabilities
- 2010
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Ingår i: BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS. - : Elsevier Science B.V., Amsterdam. - 0006-291X .- 1090-2104. ; 396:1, s. 125-130
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Tidskriftsartikel (refereegranskat)abstract
- Two large gene and protein superfamilies, SDR and MDR (short- and medium-chain dehydrogenases/reductases), were originally defined from analysis of alcohol and polyol dehydrogenases. The superfamilies contain minimally 82 and 25 genes, respectively, in humans, minimally 324 and 86 enzyme families when known lines in other organisms are also included, and over 47,000 and 15,000 variants in existing sequence data bank entries. SDR enzymes have one-domain subunits without metal and MDR two-domain subunits without or with zinc, and these three lines appear to have emerged in that order from the universal cellular ancestor. This is compatible with their molecular architectures, present multiplicity, and overall distribution in the kingdoms of life, with SDR also of viral occurrence. An MDR-zinc, when present, is often, but not always, catalytic. It appears also to have a structural role in inter-domain interactions, coenzyme binding and substrate pocket formation, as supported by domain variability ratios and ligand positions. Differences among structural and catalytic zinc ions may be relative and involve several states. Combined, the comparisons trace evolutionary properties of huge superfamilies, with partially redundant enzymes in cellular redox functions.
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| 4. |
- Kallberg, Yvonne, et al.
(författare)
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Classification of the short-chain dehydrogenase/reductase superfamily using hidden Markov models
- 2010
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Ingår i: FEBS JOURNAL. - : Blackwell Publishing Ltd. - 1742-464X .- 1742-4658. ; 277:10, s. 2375-2386
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Tidskriftsartikel (refereegranskat)abstract
- The short-chain dehydrogenase/reductase (SDR) superfamily now has over 47 000 members, most of which are distantly related, with typically 20-30% residue identity in pairwise comparisons, making it difficult to obtain an overview of this superfamily. We have therefore developed a family classification system, based upon hidden Markov models (HMMs). To this end, we have identified 314 SDR families, encompassing about 31 900 members. In addition, about 9700 SDR forms belong to families with too few members at present to establish valid HMMs. In the human genome, we find 47 SDR families, corresponding to 82 genes. Thirteen families are present in all three domains (Eukaryota, Bacteria, and Archaea), and are hence expected to catalyze fundamental metabolic processes. The majority of these enzymes are of the extended type, in agreement with earlier findings. About half of the SDR families are only found among bacteria, where the classical SDR type is most prominent. The HMM-based classification is used as a basis for a sustainable and expandable nomenclature system.
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| 5. |
- Newman, Joseph A., et al.
(författare)
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Structures of Two Melanoma-Associated Antigens Suggest Allosteric Regulation of Effector Binding
- 2016
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 11:2
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Tidskriftsartikel (refereegranskat)abstract
- The MAGE (melanoma associated antigen) protein family are tumour-associated proteins normally present only in reproductive tissues such as germ cells of the testis. The human genome encodes over 60 MAGE genes of which one class (containing MAGE-A3 and MAGE-A4) are exclusively expressed in tumours, making them an attractive target for the development of targeted and immunotherapeutic cancer treatments. Some MAGE proteins are thought to play an active role in driving cancer, modulating the activity of E3 ubiquitin ligases on targets related to apoptosis. Here we determined the crystal structures of MAGE-A3 and MAGE-A4. Both proteins crystallized with a terminal peptide bound in a deep cleft between two tandem-arranged winged helix domains. MAGE-A3 (but not MAGE-A4), is predominantly dimeric in solution. Comparison of MAGE-A3 and MAGE-A3 with a structure of an effector-bound MAGE-G1 suggests that a major conformational rearrangement is required for binding, and that this conformational plasticitymay be targeted by allosteric binders.
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| 6. |
- Persson, Bengt, et al.
(författare)
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The SDR (short-chain dehydrogenase/reductase and related enzymes) nomenclature initiative
- 2009
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Ingår i: Chemico-Biological Interactions. - : Elsevier BV. - 0009-2797 .- 1872-7786. ; 178:1-3, s. 94-98
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Tidskriftsartikel (refereegranskat)abstract
- Short-chain dehydrogenases/reductases (SDR) constitute one of the largest enzyme superfamilies with presently over 46,000 members. In phylogenetic comparisons, members of this superfamily show early divergence where the majority have only low pairwise sequence identity, although sharing common structural properties. The SDR enzymes are present in virtually all genomes investigated, and in humans over 70 SDR genes have been identified. In humans, these enzymes are involved in the metabolism of a large variety of compounds, including steroid hormones, prostaglandins, retinoids, lipids and xenobiotics. It is now clear that SDRs represent one of the oldest protein families and contribute to essential functions and interactions of all forms of life. As this field continues to grow rapidly, a systematic nomenclature is essential for future annotation and reference purposes. A functional subdivision of the SDR superfamily into at least 200 SDR families based upon hidden Markov models forms a suitable foundation for such a nomenclature system, which we present in this paper using human SDRs as examples.
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