scholarly journals Crystal Structure of SEDL and Its Implications for a Genetic Disease Spondyloepiphyseal Dysplasia Tarda

2002 ◽  
Vol 277 (51) ◽  
pp. 49863-49869 ◽  
Author(s):  
Se Bok Jang ◽  
Yeon-Gil Kim ◽  
Yong-Soon Cho ◽  
Pann-Ghill Suh ◽  
Kyung-Hwa Kim ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Genetic Disease ◽  
Point Mutations ◽  
Missense Mutations ◽  
Protein Protein Interactions ◽  
Spondyloepiphyseal Dysplasia ◽  
Multiple Protein ◽  
Protein Particle ◽  
Eukaryotic Organisms ◽  
Spondyloepiphyseal Dysplasia Tarda

SEDL is an evolutionarily highly conserved protein in eukaryotic organisms. Deletions or point mutations in theSEDLgene are responsible for the genetic disease spondyloepiphyseal dysplasia tarda (SEDT), an X-linked skeletal disorder. SEDL has been identified as a component of the transport protein particle (TRAPP), critically involved in endoplasmic reticulum-to-Golgi vesicle transport. Herein, we report the 2.4 Å resolution structure of SEDL, which reveals an unexpected similarity to the structures of the N-terminal regulatory domain of two SNAREs, Ykt6p and Sec22b, despite no sequence homology to these proteins. The similarity and the presence of unusually many solvent-exposed apolar residues of SEDL suggest that it serves regulatory and/or adaptor functions through multiple protein-protein interactions. Of the four known missense mutations responsible for SEDT, three mutations (S73L, F83S, V130D) map to the protein interior, where the mutations would disrupt the structure, and the fourth (D47Y) on a surface at which the mutation may abrogate functional interactions with a partner protein.

Biochemical consequences of sedlin mutations that cause spondyloepiphyseal dysplasia tarda

2009 ◽  
Vol 423 (2) ◽  
pp. 233-242 ◽  
Author(s):  
Mei Y. Choi ◽  
Caleb C. Y. Chan ◽  
Danny Chan ◽  
Keith D. K. Luk ◽  
Kathryn S. E. Cheah ◽  
...  
Keyword(s):  
Late Onset ◽  
Transport Protein ◽  
Missense Mutations ◽  
Wild Type ◽  
Spondyloepiphyseal Dysplasia ◽  
Type Protein ◽  
Wild Type Protein ◽  
Protein Particle ◽  
Spondyloepiphyseal Dysplasia Tarda

SEDT (spondyloepiphyseal dysplasia tarda) is a late-onset X-linked recessive skeletal dysplasia caused by mutations in the gene SEDL coding for sedlin. In the present paper, we investigated four missense mutations observed in SEDT and compare biochemical and cellular characteristics relative to the wild-type protein to address the mechanism of disease and to gain insight into the function of the sedlin protein. In situ hybridization and immunohistochemical experiments in mouse growth plates revealed sedlin to be predominantly expressed in proliferating and hypertrophic chondrocytes. Cell culture studies showed that the wild-type protein localized predominantly in the vicinity of the nucleus and the Golgi, with further localization around the cytoplasm, whereas mutation resulted in mislocalization. The D47Y mutant was expressed similarly to the wild-type, but the S73L, F83S and V130D mutants showed particularly low levels of expression that were rescued in the presence of the proteasome inhibitor MG132 (benzyloxycarbonyl-leucylleucylleucinal). Furthermore, whereas the D47Y mutant folded similarly and had similar stability to the wild-type sedlin as shown by CD and fluorescence, the S73L, F83S and V130D mutants all misfolded during expression. Two independent assays showed that the D47Y mutation resulted in an increased affinity for the transport protein particle component Bet3 compared with the wild-type sedlin. Our results suggest that the sedlin mutations S73L, F83S and V130D cause SEDT by sedlin misfolding, whereas the D47Y mutation may influence normal TRAPP (transport protein particle) dynamics.

scholarly journals POT1-TPP1 differentially regulates telomerase via POT1 His266 and as a function of single-stranded telomere DNA length

2019 ◽  
Vol 116 (47) ◽  
pp. 23527-23533 ◽  
Author(s):  
Mengyuan Xu ◽  
Janna Kiselar ◽  
Tawna L. Whited ◽  
Wilnelly Hernandez-Sanchez ◽  
Derek J. Taylor
Keyword(s):  
Conformational Changes ◽  
Protein Interactions ◽  
Environmental Changes ◽  
Lymphocytic Leukemia ◽  
Protein Protein Interactions ◽  
Cellular Environment ◽  
Multiple Protein ◽  
Linear Chromosomes ◽  
Hydroxyl Radical Footprinting ◽  
Regulate Telomere Length

Telomeres cap the ends of linear chromosomes and terminate in a single-stranded DNA (ssDNA) overhang recognized by POT1-TPP1 heterodimers to help regulate telomere length homeostasis. Here hydroxyl radical footprinting coupled with mass spectrometry was employed to probe protein–protein interactions and conformational changes involved in the assembly of telomere ssDNA substrates of differing lengths bound by POT1-TPP1 heterodimers. Our data identified environmental changes surrounding residue histidine 266 of POT1 that were dependent on telomere ssDNA substrate length. We further determined that the chronic lymphocytic leukemia-associated H266L substitution significantly reduced POT1-TPP1 binding to short ssDNA substrates; however, it only moderately impaired the heterodimer binding to long ssDNA substrates containing multiple protein binding sites. Additionally, we identified a telomerase inhibitory role when several native POT1-TPP1 proteins coat physiologically relevant lengths of telomere ssDNA. This POT1-TPP1 complex-mediated inhibition of telomerase is abrogated in the context of the POT1 H266L mutation, which leads to telomere overextension in a malignant cellular environment.

scholarly journals Mechanism and bottlenecks in strand photodissociation of split green fluorescent proteins (GFPs)

2017 ◽  
Vol 114 (11) ◽  
pp. E2146-E2155 ◽  
Author(s):  
Chi-Yun Lin ◽  
Johan Both ◽  
Keunbong Do ◽  
Steven G. Boxer
Keyword(s):  
Quantum Yield ◽  
Protein Interactions ◽  
Fluorescent Proteins ◽  
Point Mutations ◽  
Photoactive Yellow Protein ◽  
Green Fluorescent Proteins ◽  
Protein Protein Interactions ◽  
Low Efficiency ◽  
Green Fluorescent ◽  
Rate Limiting

Split GFPs have been widely applied for monitoring protein–protein interactions by expressing GFPs as two or more constituent parts linked to separate proteins that only fluoresce on complementing with one another. Although this complementation is typically irreversible, it has been shown previously that light accelerates dissociation of a noncovalently attached β-strand from a circularly permuted split GFP, allowing the interaction to be reversible. Reversible complementation is desirable, but photodissociation has too low of an efficiency (quantum yield <1%) to be useful as an optogenetic tool. Understanding the physical origins of this low efficiency can provide strategies to improve it. We elucidated the mechanism of strand photodissociation by measuring the dependence of its rate on light intensity and point mutations. The results show that strand photodissociation is a two-step process involving light-activated cis-trans isomerization of the chromophore followed by light-independent strand dissociation. The dependence of the rate on temperature was then used to establish a potential energy surface (PES) diagram along the photodissociation reaction coordinate. The resulting energetics–function model reveals the rate-limiting process to be the transition from the electronic excited-state to the ground-state PES accompanying cis-trans isomerization. Comparisons between split GFPs and other photosensory proteins, like photoactive yellow protein and rhodopsin, provide potential strategies for improving the photodissociation quantum yield.

scholarly journals Competition NMR for Detection of Hit/Lead Inhibitors of Protein–Protein Interactions

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3017 ◽  
Author(s):  
Bogdan Musielak ◽  
Weronika Janczyk ◽  
Ismael Rodriguez ◽  
Jacek Plewka ◽  
Dominik Sala ◽  
...  
Keyword(s):  
Small Molecule ◽  
Protein Interactions ◽  
Point Mutations ◽  
Protein Protein Interactions ◽  
Competition Assay ◽  
Fragment Screening ◽  
Different Types ◽  
Lead Inhibitors

Screening for small-molecule fragments that can lead to potent inhibitors of protein–protein interactions (PPIs) is often a laborious step as the fragments cannot dissociate the targeted PPI due to their low μM–mM affinities. Here, we describe an NMR competition assay called w-AIDA-NMR (weak-antagonist induced dissociation assay-NMR), which is sensitive to weak μM–mM ligand–protein interactions and which can be used in initial fragment screening campaigns. By introducing point mutations in the complex’s protein that is not targeted by the inhibitor, we lower the effective affinity of the complex, allowing for short fragments to dissociate the complex. We illustrate the method with the compounds that block the Mdm2/X-p53 and PD-1/PD-L1 oncogenic interactions. Targeting the PD-/PD-L1 PPI has profoundly advanced the treatment of different types of cancers.

scholarly journals Conserved HORMA domain-containing protein Hop1 stabilizes interaction between proteins of meiotic DNA break hotspots and chromosome axis

2019 ◽  
Vol 47 (19) ◽  
pp. 10166-10180 ◽  
Author(s):  
Ryo Kariyazono ◽  
Arisa Oda ◽  
Takatomi Yamada ◽  
Kunihiro Ohta
Keyword(s):  
Fission Yeast ◽  
Protein Interactions ◽  
Meiotic Recombination ◽  
Protein Protein Interactions ◽  
Dna Double Strand Breaks ◽  
Strand Breaks ◽  
Multiple Protein ◽  
Chromatin Immunoprecipitation Sequencing ◽  
The One ◽  
Chromosome Axis

Abstract HORMA domain-containing proteins such as Hop1 play crucial regulatory roles in various chromosomal functions. Here, we investigated roles of the fission yeast Hop1 in the formation of recombination-initiating meiotic DNA double strand breaks (DSBs). Meiotic DSB formation in fission yeast relies on multiple protein-protein interactions such as the one between the chromosome axial protein Rec10 and the DSB-forming complex subunit Rec15. Chromatin immunoprecipitation sequencing demonstrated that Hop1 is colocalized with both Rec10 and Rec15, and we observed physical interactions of Hop1 to Rec15 and Rec10. These results suggest that Hop1 promotes DSB formation by interacting with both axis components and the DSB-forming complex. We also show that Hop1 binding to DSB hotspots requires Rec15 and Rec10, while Hop1 axis binding requires Rec10 only, suggesting that Hop1 is recruited to the axis via Rec10, and to hotspots by hotspot-bound Rec15. Furthermore, we introduced separation-of-function Rec10 mutations, deficient for interaction with either Rec15 or Hop1. These single mutations and hop1Δ conferred only partial defects in meiotic recombination, while the combining the Rec15-binding-deficient rec10 mutation with hop1Δ synergistically reduced meiotic recombination, at least at a model hotspot. Taken together, Hop1 likely functions as a stabilizer for Rec15–Rec10 interaction to promote DSB formation.

scholarly journals mCSM-PPI2: predicting the effects of mutations on protein–protein interactions

2019 ◽  
Vol 47 (W1) ◽  
pp. W338-W344 ◽  
Author(s):  
Carlos H M Rodrigues ◽  
Yoochan Myung ◽  
Douglas E V Pires ◽  
David B Ascher
Keyword(s):  
Protein Interactions ◽  
Interaction Network ◽  
Evolutionary Information ◽  
Biological Processes ◽  
Missense Mutations ◽  
Protein Protein Interactions ◽  
Protein Protein Interaction ◽  
Residue Interaction ◽  
User Friendly ◽  
Network Metrics

AbstractProtein–protein Interactions are involved in most fundamental biological processes, with disease causing mutations enriched at their interfaces. Here we present mCSM-PPI2, a novel machine learning computational tool designed to more accurately predict the effects of missense mutations on protein–protein interaction binding affinity. mCSM-PPI2 uses graph-based structural signatures to model effects of variations on the inter-residue interaction network, evolutionary information, complex network metrics and energetic terms to generate an optimised predictor. We demonstrate that our method outperforms previous methods, ranking first among 26 others on CAPRI blind tests. mCSM-PPI2 is freely available as a user friendly webserver at http://biosig.unimelb.edu.au/mcsm_ppi2/.

scholarly journals Structure of the Notch1-negative regulatory region: implications for normal activation and pathogenic signaling in T-ALL

Blood ◽  
2009 ◽  
Vol 113 (18) ◽  
pp. 4381-4390 ◽  
Author(s):  
Wendy R. Gordon ◽  
Monideepa Roy ◽  
Didem Vardar-Ulu ◽  
Megan Garfinkel ◽  
Marc R. Mansour ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Structural Integrity ◽  
Crystal Packing ◽  
Novel Mutation ◽  
Lymphoblastic Leukemia ◽  
Regulatory Region ◽  
Point Mutations ◽  
Protein Protein Interactions ◽  
Proteolytic Resistance ◽  
Cell Acute Lymphoblastic Leukemia

Abstract Proteolytic resistance of Notch prior to ligand binding depends on the structural integrity of a negative regulatory region (NRR) of the receptor that immediately precedes the transmembrane segment. The NRR includes the 3 Lin12/Notch repeats and the juxtamembrane heterodimerization domain, the region of Notch1 most frequently mutated in T-cell acute lymphoblastic leukemia lymphoma (T-ALL). Here, we report the x-ray structure of the Notch1 NRR in its autoinhibited conformation. A key feature of the Notch1 structure that maintains its closed conformation is a conserved hydrophobic plug that sterically occludes the metalloprotease cleavage site. Crystal packing interactions involving a highly conserved, exposed face on the third Lin12/Notch repeat suggest that this site may normally be engaged in intermolecular or intramolecular protein-protein interactions. The majority of known T-ALL–associated point mutations map to residues in the hydrophobic interior of the Notch1 NRR. A novel mutation (H1545P), which alters a residue at the crystal-packing interface, leads to ligand-independent increases in signaling in reporter gene assays despite only mild destabilization of the NRR, suggesting that it releases the autoinhibitory clamp on the heterodimerization domain imposed by the Lin12/Notch repeats. The Notch1 NRR structure should facilitate a search for antibodies or compounds that stabilize the autoinhibited conformation.

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