The domain-specific and temperature-dependent protein misfolding phenotype of variant medium-chain acyl-CoA dehydrogenase

TY - JOUR

T1 - The domain-specific and temperature-dependent protein misfolding phenotype of variant medium-chain acyl-CoA dehydrogenase

AU - Jank, Johanna M

AU - Maier, Esther M

AU - Reiβ, Dunja D

AU - Haslbeck, Martin

AU - Kemter, Kristina F

AU - Truger, Marietta S

AU - Sommerhoff, Christian P

AU - Ferdinandusse, Sacha

AU - Wanders, Ronald J

AU - Gersting, Søren W

AU - Muntau, Ania C

PY - 2014/1/1

Y1 - 2014/1/1

N2 - The implementation of expanded newborn screening programs reduced mortality and morbidity in medium-chain acyl-CoA dehydrogenase deficiency (MCADD) caused by mutations in the ACADM gene. However, the disease is still potentially fatal. Missense induced MCADD is a protein misfolding disease with a molecular loss-of-function phenotype. Here we established a comprehensive experimental setup to analyze the structural consequences of eight ACADM missense mutations (p.Ala52Val, p.Tyr67His, p.Tyr158His, p.Arg206Cys, p.Asp266Gly, p.Lys329Glu, p.Arg334Lys, p.Arg413Ser) identified after newborn screening and linked the corresponding protein misfolding phenotype to the site of side-chain replacement with respect to the domain. With fever being the crucial risk factor for metabolic decompensation of patients with MCADD, special emphasis was put on the analysis of structural and functional derangements related to thermal stress. Based on protein conformation, thermal stability and kinetic stability, the molecular phenotype in MCADD depends on the structural region that is affected by missense-induced conformational changes with the central β-domain being particularly prone to structural derangement and destabilization. Since systematic classification of conformational derangements induced by ACADM mutations may be a helpful tool in assessing the clinical risk of patients, we scored the misfolding phenotype of the variants in comparison to p.Lys329Glu (K304E), the classical severe mutation, and p.Tyr67His (Y42H), discussed to be mild. Experiments assessing the impact of thermal stress revealed that mutations in the ACADM gene lower the temperature threshold at which MCAD loss-of-function occurs. Consequently, increased temperature as it occurs during intercurrent infections, significantly increases the risk of further conformational derangement and loss of function of the MCAD enzyme explaining the life-threatening clinical courses observed during fever episodes. Early and aggressive antipyretic treatment thus may be life-saving in patients suffering from MCADD.

AB - The implementation of expanded newborn screening programs reduced mortality and morbidity in medium-chain acyl-CoA dehydrogenase deficiency (MCADD) caused by mutations in the ACADM gene. However, the disease is still potentially fatal. Missense induced MCADD is a protein misfolding disease with a molecular loss-of-function phenotype. Here we established a comprehensive experimental setup to analyze the structural consequences of eight ACADM missense mutations (p.Ala52Val, p.Tyr67His, p.Tyr158His, p.Arg206Cys, p.Asp266Gly, p.Lys329Glu, p.Arg334Lys, p.Arg413Ser) identified after newborn screening and linked the corresponding protein misfolding phenotype to the site of side-chain replacement with respect to the domain. With fever being the crucial risk factor for metabolic decompensation of patients with MCADD, special emphasis was put on the analysis of structural and functional derangements related to thermal stress. Based on protein conformation, thermal stability and kinetic stability, the molecular phenotype in MCADD depends on the structural region that is affected by missense-induced conformational changes with the central β-domain being particularly prone to structural derangement and destabilization. Since systematic classification of conformational derangements induced by ACADM mutations may be a helpful tool in assessing the clinical risk of patients, we scored the misfolding phenotype of the variants in comparison to p.Lys329Glu (K304E), the classical severe mutation, and p.Tyr67His (Y42H), discussed to be mild. Experiments assessing the impact of thermal stress revealed that mutations in the ACADM gene lower the temperature threshold at which MCAD loss-of-function occurs. Consequently, increased temperature as it occurs during intercurrent infections, significantly increases the risk of further conformational derangement and loss of function of the MCAD enzyme explaining the life-threatening clinical courses observed during fever episodes. Early and aggressive antipyretic treatment thus may be life-saving in patients suffering from MCADD.

KW - Acyl-CoA Dehydrogenase

KW - Animals

KW - COS Cells

KW - Cercopithecus aethiops

KW - Circular Dichroism

KW - Enzyme Activation

KW - Flavin-Adenine Dinucleotide

KW - Fluorescence

KW - Hot Temperature

KW - Humans

KW - Hydrophobic and Hydrophilic Interactions

KW - Kinetics

KW - Models, Molecular

KW - Mutant Proteins

KW - Mutation, Missense

KW - Phenotype

KW - Protein Aggregates

KW - Protein Denaturation

KW - Protein Folding

KW - Protein Structure, Secondary

KW - Protein Structure, Tertiary

KW - Temperature

U2 - 10.1371/journal.pone.0093852

DO - 10.1371/journal.pone.0093852

M3 - SCORING: Journal article

C2 - 24718418

VL - 9

SP - e93852

JO - PLOS ONE

JF - PLOS ONE

SN - 1932-6203

IS - 4

ER -