scholarly journals Structure of the Complete Dimeric Human GDAP1 Core Domain Provides Insights into Ligand Binding and Clustering of Disease Mutations

2021 ◽  
Vol 7 ◽  
Author(s):  
Giang Thi Tuyet Nguyen ◽  
Aleksi Sutinen ◽  
Arne Raasakka ◽  
Gopinath Muruganandam ◽  
Remy Loris ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Glutathione S Transferase ◽  
Oligomeric State ◽  
Core Domain ◽  
Charcot Marie Tooth Disease ◽  
Disease Mutations ◽  
And Function ◽  
Allosteric Mechanisms ◽  
Gst Family ◽  
Tooth Disease

Charcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders. Despite the common involvement of ganglioside-induced differentiation-associated protein 1 (GDAP1) in CMT, the protein structure and function, as well as the pathogenic mechanisms, remain unclear. We determined the crystal structure of the complete human GDAP1 core domain, which shows a novel mode of dimerization within the glutathione S-transferase (GST) family. The long GDAP1-specific insertion forms an extended helix and a flexible loop. GDAP1 is catalytically inactive toward classical GST substrates. Through metabolite screening, we identified a ligand for GDAP1, the fatty acid hexadecanedioic acid, which is relevant for mitochondrial membrane permeability and Ca2+ homeostasis. The fatty acid binds to a pocket next to a CMT-linked residue cluster, increases protein stability, and induces changes in protein conformation and oligomerization. The closest homologue of GDAP1, GDAP1L1, is monomeric in its full-length form. Our results highlight the uniqueness of GDAP1 within the GST family and point toward allosteric mechanisms in regulating GDAP1 oligomeric state and function.

scholarly journals Structure of the complete dimeric human GDAP1 core domain provides insights into ligand binding and clustering of disease mutations

2020 ◽  
Author(s):  
Giang Thi Tuyet Nguyen ◽  
Aleksi Sutinen ◽  
Arne Raasakka ◽  
Gopinath Muruganandam ◽  
Remy Loris ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Glutathione S Transferase ◽  
Oligomeric State ◽  
Core Domain ◽  
Charcot Marie Tooth Disease ◽  
Disease Mutations ◽  
And Function ◽  
Allosteric Mechanisms ◽  
Gst Family ◽  
Tooth Disease

ABSTRACTCharcot-Marie-Tooth disease (CMT) is one of the most common inherited neurological disorders. Despite the common involvement of ganglioside-induced differentiation-associated protein 1 (GDAP1) in CMT, the protein structure and function, as well as the pathogenic mechanisms, remain unclear. We determined the crystal structure of the complete human GDAP1 core domain, which shows a novel mode of dimerization within the glutathione S-transferase (GST) family. The long GDAP1-specific insertion forms an extended helix and a flexible loop. GDAP1 is catalytically inactive towards classical GST substrates. Through metabolite screening, we identified a ligand for GDAP1, the fatty acid hexadecanedioic acid, which is relevant for mitochondrial membrane permeability and Ca2+ homeostasis. The fatty acid binds to a pocket next to a CMT-linked residue cluster, increases protein stability, and induces changes in protein conformation and oligomerization. The closest homologue of GDAP1, GDAP1L1, is monomeric in its full-length form. Our results highlight the uniqueness of GDAP1 within the GST family and point towards allosteric mechanisms in regulating GDAP1 oligomeric state and function.

scholarly journals Mutations in GDAP1 Influence Structure and Function of the Trans-Golgi Network

2021 ◽  
Vol 22 (2) ◽  
pp. 914
Author(s):  
Katarzyna Binięda ◽  
Weronika Rzepnikowska ◽  
Damian Kolakowski ◽  
Joanna Kaminska ◽  
Andrzej Antoni Szczepankiewicz ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Experimental Therapy ◽  
Negative Effects ◽  
Gene Encoding ◽  
Charcot Marie Tooth Disease ◽  
Terra Incognita ◽  
And Function ◽  
Golgi Network ◽  
Cell Phenotypes ◽  
Tooth Disease

Charcot-Marie-Tooth disease (CMT) is a heritable neurodegenerative disease that displays great genetic heterogeneity. The genes and mutations that underlie this heterogeneity have been extensively characterized by molecular genetics. However, the molecular pathogenesis of the vast majority of CMT subtypes remains terra incognita. Any attempts to perform experimental therapy for CMT disease are limited by a lack of understanding of the pathogenesis at a molecular level. In this study, we aim to identify the molecular pathways that are disturbed by mutations in the gene encoding GDAP1 using both yeast and human cell, based models of CMT-GDAP1 disease. We found that some mutations in GDAP1 led to a reduced expression of the GDAP1 protein and resulted in a selective disruption of the Golgi apparatus. These structural alterations are accompanied by functional disturbances within the Golgi. We screened over 1500 drugs that are available on the market using our yeast-based CMT-GDAP1 model. Drugs were identified that had both positive and negative effects on cell phenotypes. To the best of our knowledge, this study is the first report of the Golgi apparatus playing a role in the pathology of CMT disorders. The drugs we identified, using our yeast-based CMT-GDAP1 model, may be further used in translational research.

scholarly journals Complementation between mouse Mfn1 and Mfn2 protects mitochondrial fusion defects caused by CMT2A disease mutations

2007 ◽  
Vol 176 (4) ◽  
pp. 405-414 ◽  
Author(s):  
Scott A. Detmer ◽  
David C. Chan
Keyword(s):  
Axonal Degeneration ◽  
Mitochondrial Protein ◽  
Mitochondrial Fusion ◽  
Wild Type ◽  
Cell Type ◽  
Charcot Marie Tooth Disease ◽  
Disease Mutations ◽  
Cell Type Specific ◽  
In Trans ◽  
Tooth Disease

Mfn2, an oligomeric mitochondrial protein important for mitochondrial fusion, is mutated in Charcot-Marie-Tooth disease (CMT) type 2A, a peripheral neuropathy characterized by axonal degeneration. In addition to homooligomeric complexes, Mfn2 also associates with Mfn1, but the functional significance of such heterooligomeric complexes is unknown. Also unknown is why Mfn2 mutations in CMT2A lead to cell type–specific defects given the widespread expression of Mfn2. In this study, we show that homooligomeric complexes formed by many Mfn2 disease mutants are nonfunctional for mitochondrial fusion. However, wild-type Mfn1 complements mutant Mfn2 through the formation of heterooligomeric complexes, including complexes that form in trans between mitochondria. Wild-type Mfn2 cannot complement the disease alleles. Our results highlight the functional importance of Mfn1–Mfn2 heterooligomeric complexes and the close interplay between the two mitofusins in the control of mitochondrial fusion. Furthermore, they suggest that tissues with low Mfn1 expression are vulnerable in CMT2A and that methods to increase Mfn1 expression in the peripheral nervous system would benefit CMT2A patients.

scholarly journals A complex containing lysine-acetylated actin inhibits the formin INF2

2018 ◽  
Author(s):  
Mu A ◽  
Tak Shun Fung ◽  
Arminja N. Kettenbach ◽  
Rajarshi Chakrabarti ◽  
Henry Higgs
Keyword(s):  
Actin Binding ◽  
Actin Assembly ◽  
Histone Deacetylase 6 ◽  
Charcot Marie Tooth ◽  
Charcot Marie Tooth Disease ◽  
Disease Mutations ◽  
Assembly Factor ◽  
Inhibitory Domain ◽  
Cellular Inhibitors ◽  
Tooth Disease

INF2 is a member of the formin family of actin assembly factors. Dominant mis-sense mutations in INF2 link to two diseases: focal segmental glomerulosclerosis (FSGS), a kidney disease; and Charcot-Marie-Tooth disease (CMTD), a neuropathy. All disease mutations map to the autoinhibitory Diaphanous Inhibitory Domain (DID). Curiously, purified INF2 is not autoinhibited, suggesting the existence of additional cellular inhibitors. We purified an INF2 inhibitor from mouse brain, and identified it as a complex between lysine-acetylated actin (KAc-actin) and cyclase-associated protein (CAP). Inhibition of INF2 by CAP/KAc-actin requires INF2 DID. Treatment of CAP/KAc-actin with histone deacetylase 6 (HDAC6) releases INF2 inhibition, while HDAC6 inhibitors block cellular INF2 activation. INF2 disease mutants are poorly inhibited by CAP/KAc-actin, suggesting that FSGS and CMTD result from reduced CAP/KAc-actin binding. This is the first demonstrated role for lysine-acetylated actin: regulation of an actin assembly factor by a novel mechanism, which we call facilitated auto-inhibition.

scholarly journals KIF1Bβ mutations detected in hereditary neuropathy impair IGF1R transport and axon growth

2018 ◽  
Vol 217 (10) ◽  
pp. 3480-3496 ◽  
Author(s):  
Fang Xu ◽  
Hironori Takahashi ◽  
Yosuke Tanaka ◽  
Sotaro Ichinose ◽  
Shinsuke Niwa ◽  
...  
Keyword(s):  
Neuronal Development ◽  
Binding Capacity ◽  
Axon Growth ◽  
Hereditary Neuropathy ◽  
Binding Partner ◽  
Charcot Marie Tooth Disease ◽  
Direct Binding ◽  
And Function ◽  
Igf1r Expression ◽  
Tooth Disease

KIF1Bβ is a kinesin-3 family anterograde motor protein essential for neuronal development, viability, and function. KIF1Bβ mutations have previously been reported in a limited number of pedigrees of Charcot-Marie-Tooth disease type 2A (CMT2A) neuropathy. However, the gene responsible for CMT2A is still controversial, and the mechanism of pathogenesis remains elusive. In this study, we show that the receptor tyrosine kinase IGF1R is a new direct binding partner of KIF1Bβ, and its binding and transport is specifically impaired by the Y1087C mutation of KIF1Bβ, which we detected in hereditary neuropathic patients. The axonal outgrowth and IGF-I signaling of Kif1b−/− neurons were significantly impaired, consistent with decreased surface IGF1R expression. The complementary capacity of KIF1Bβ-Y1087C of these phenotypes was significantly impaired, but the binding capacity to synaptic vesicle precursors was not affected. These data have supported the relevance of KIF1Bβ in IGF1R transport, which may give new clue to the neuropathic pathogenesis.

scholarly journals Neuropathic mutations in MORC2 perturb GHKL ATPase dimerization dynamics and epigenetic silencing by multiple structural mechanisms

2017 ◽  
Author(s):  
Christopher H. Douse ◽  
Stuart Bloor ◽  
Yangci Liu ◽  
Maria Shamin ◽  
Iva A. Tchasovnikarova ◽  
...  
Keyword(s):  
Muscular Atrophy ◽  
Coiled Coil ◽  
Epigenetic Silencing ◽  
Missense Mutations ◽  
Wild Type ◽  
Dimer Interface ◽  
Charcot Marie Tooth Disease ◽  
Disease Mutations ◽  
Structural Mechanisms ◽  
Tooth Disease

AbstractMissense mutations in MORC2 cause neuropathies including spinal muscular atrophy and Charcot-Marie-Tooth disease. We recently identified MORC2 as an effector of epigenetic silencing by the HUSH complex. Here we report the biochemical and cellular activities of MORC2 variants, alongside crystal structures of wild-type and neuropathic forms of a human MORC2 fragment comprising the GHKL-type ATPase module and CW-type zinc finger. This fragment dimerizes upon binding ATP and contains a hinged, functionally critical coiled coil insertion absent in other GHKL ATPases. We find that dimerization and DNA binding of the MORC2 ATPase module transduce HUSH-dependent silencing. Disease mutations change the dynamics of dimerization by distinct structural mechanisms: destabilizing the ATPase-CW module, trapping the ATP lid or perturbing the dimer interface. These defects lead to modulation of HUSH function, thus providing a molecular basis for understanding MORC2-associated neuropathies.

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