Regulation of ATP-dependent chromatin remodelers: accelerators/brakes, anchors and sensors

2018 ◽  
Vol 46 (6) ◽  
pp. 1423-1430 ◽  
Author(s):  
Somnath Paul ◽  
Blaine Bartholomew
Keyword(s):  
Protein Interactions ◽  
Atp Hydrolysis ◽  
Self Regulation ◽  
Protein Protein Interactions ◽  
Dna Translocation ◽  
Chromatin Remodelers ◽  
Histone Octamer ◽  
Double Stranded Dna ◽  
Accessory Subunits ◽  
Dna Translocase

All ATP-dependent chromatin remodelers have a DNA translocase domain that moves along double-stranded DNA when hydrolyzing ATP, which is the key action leading to DNA moving through nucleosomes. Recent structural and biochemical data from a variety of different chromatin remodelers have revealed that there are three basic ways in which these remodelers self-regulate their chromatin remodeling activity. In several instances, different domains within the catalytic subunit or accessory subunits through direct protein–protein interactions can modulate the ATPase and DNA translocation properties of the DNA translocase domain. These domains or subunits can stabilize conformations that either promote or interfere with the ability of the translocase domain to bind or retain DNA during translocation or alter the ability of the enzyme to hydrolyze ATP. Second, other domains or subunits are often necessary to anchor the remodeler to nucleosomes to couple DNA translocation and ATP hydrolysis to DNA movement around the histone octamer. These anchors provide a fixed point by which remodelers can generate sufficient torque to disrupt histone–DNA interactions and mobilize nucleosomes. The third type of self-regulation is in those chromatin remodelers that space nucleosomes or stop moving nucleosomes when a particular length of linker DNA has been reached. We refer to this third class as DNA sensors that can allosterically regulate nucleosome mobilization. In this review, we will show examples of these from primarily the INO80/SWR1, SWI/SNF and ISWI/CHD families of remodelers.

scholarly journals Domains of alpha-SNAP required for the stimulation of exocytosis and for N-ethylmalemide-sensitive fusion protein (NSF) binding and activation.

1996 ◽  
Vol 7 (5) ◽  
pp. 693-701 ◽  
Author(s):  
R J Barnard ◽  
A Morgan ◽  
R D Burgoyne
Keyword(s):  
Membrane Proteins ◽  
Fusion Protein ◽  
Conformational Changes ◽  
Protein Interactions ◽  
Atp Hydrolysis ◽  
Coiled Coil ◽  
Protein Protein Interactions ◽  
Permeabilized Cells ◽  
C Terminus ◽  
Adrenal Chromaffin

The binding of alpha-SNAP to the membrane proteins syntaxin, SNAP-25, and synaptobrevin leads to the recruitment of the N-ethylmaleimide-sensitive fusion protein (NSF). ATP hydrolysis by NSF has been suggested to drive conformational changes in one or more of these membrane proteins that are essential for regulated exocytosis. Functional evidence for a role of alpha-SNAP in exocytosis in adrenal chromaffin cells comes from the ability of this protein to stimulate Ca(2+)-dependent exocytosis in digitonin-permeabilized cells. Here we examine the effect of a series of deletion mutants of alpha-SNAP on exocytosis, and on the ability of alpha-SNAP to interact with NSF, to define essential domains involved in protein-protein interactions in exocytosis. Deletion of extreme N- or C-terminal regions of alpha-SNAP produced proteins unable to bind to syntaxin or to stimulate exocytosis, suggesting that these domains participate in essential interactions. Deletion of C-terminal residues abolished the ability of alpha-SNAP to bind NSF. In contrast, deletion of up to 120 N-terminal residues did not prevent the binding of NSF to immobilized alpha-SNAP and such mutants were also able to stimulate the ATPase activity of NSF. These results suggest that the C-terminus, but not the N-terminus, of alpha-SNAP is crucial for interactions with NSF. The involvement of the C-terminus of alpha-SNAP, which contains a predicted coiled-coil domain, in the binding of both syntaxin and NSF would place the latter two proteins in proximity in a ternary complex whereupon the energy derived from ATP hydrolysis by NSF could induce a conformational change in syntaxin required for exocytosis to proceed.

scholarly journals Tracking chromatin state changes using μMap photo-proximity labeling

2021 ◽  
Author(s):  
Ciaran P Seath ◽  
Antony J Burton ◽  
David W. C. MacMillan ◽  
Tom W Muir
Keyword(s):  
Cell Fate ◽  
Small Molecule ◽  
Protein Interactions ◽  
Control Cell ◽  
Global Changes ◽  
Therapeutic Effects ◽  
Protein Protein Interactions ◽  
Chromatin Remodelers ◽  
Expression Levels ◽  
Epigenetic Drug

Interactions between biomolecules, particularly proteins, underlie all cellular processes, and ultimately control cell fate. Perturbation of native interactions through mutation, changes in expression levels, or external stimuli leads to altered cellular physiology and can result in either disease or therapeutic effects. Mapping these interactions and determining how they respond to stimulus is the genesis of many drug development efforts, leading to new therapeutic targets and improvements in human health. However, in the complex environment of the nucleus it is challenging to determine protein-protein interactions due to low abundance, transient or multi-valent binding, and a lack of technologies that are able to interrogate these interactions without disrupting the protein binding surface under study. Chromatin remodelers, modifying enzymes, interactors, and transcription factors can all be redirected by subtle changes to the microenvironment, causing global changes in protein expression levels and subsequent physiology. Here, we describe the Chroma-μMap method for the traceless incorporation of Ir-photosensitizers into the nuclear microenvironment using engineered split inteins. These Ir-catalysts can activate diazirine warheads to form reactive carbenes within a ~10 nm radius, cross-linking with proteins within the immediate microenvironment for analysis via quantitative chemoproteomics. We demonstrate this concept on nine different nuclear proteins with varied function and in each case, elucidating their microenvironments. Additionally, we show that this short-range proximity labelling method can reveal the critical changes in interactomes in the presence of cancer-associated mutations, as well as treatment with small-molecule inhibitors. Chroma-μMap improves our fundamental understanding of nuclear protein-protein interactions, as well as the effects that small molecule therapeutics have on the local chromatin environment, and in doing so is expected to have a significant impact on the field of epigenetic drug discovery in both academia and industry.

scholarly journals Tracking chromatin state changes using µMap photo-proximity labeling

2021 ◽  
Author(s):  
Tom Muir ◽  
Ciaran Seath ◽  
David MacMillan ◽  
Antony Burton
Keyword(s):  
Cell Fate ◽  
Small Molecule ◽  
Protein Interactions ◽  
Control Cell ◽  
Global Changes ◽  
Therapeutic Effects ◽  
Protein Protein Interactions ◽  
Chromatin Remodelers ◽  
Expression Levels ◽  
Epigenetic Drug

Abstract Interactions between biomolecules, particularly proteins, underlie all cellular processes, and ultimately control cell fate. Perturbation of native interactions through mutation, changes in expression levels, or external stimuli leads to altered cellular physiology and can result in either disease or therapeutic effects. Mapping these interactions and determining how they respond to stimulus is the genesis of many drug development efforts, leading to new therapeutic targets and improvements in human health. However, in the complex environment of the nucleus it is challenging to determine protein-protein interactions due to low abundance, transient or multi-valent binding, and a lack of technologies that are able to interrogate these interactions without disrupting the protein binding surface under study. Chromatin remodelers, modifying enzymes, interactors, and transcription factors can all be redirected by subtle changes to the microenvironment, causing global changes in protein expression levels and subsequent physiology. Here, we describe the Chroma-µMap method for the traceless incorporation of Ir-photosensitizers into the nuclear microenvironment using engineered split inteins. These Ir-catalysts can activate diazirine warheads to form reactive carbenes within a ~10 nm radius, cross-linking with proteins within the immediate microenvironment for analysis via quantitative chemoproteomics. We demonstrate this concept on nine different nuclear proteins with varied function and in each case, elucidating their microenvironments. Additionally, we show that this short-range proximity labeling method can reveal the critical changes in interactomes in the presence of cancer-associated mutations, as well as treatment with small-molecule inhibitors. Chroma-µMap improves our fundamental understand-ing of nuclear protein-protein interactions, as well as the effects that small molecule therapeutics have on the local chromatin environment, and in doing so is expected to have a significant impact on the field of epigenetic drug discovery in both academia and industry.

scholarly journals Complex Formation of Yeast Rev1 and Rev7 Proteins: a Novel Role for the Polymerase-Associated Domain

2005 ◽  
Vol 25 (21) ◽  
pp. 9734-9740 ◽  
Author(s):  
Narottam Acharya ◽  
Lajos Haracska ◽  
Robert E. Johnson ◽  
Ildiko Unk ◽  
Satya Prakash ◽  
...  
Keyword(s):  
Dna Polymerase ◽  
Protein Interactions ◽  
Synthetic Activity ◽  
Stable Complex ◽  
Abasic Site ◽  
Protein Protein Interactions ◽  
Lesion Bypass ◽  
Accessory Subunits ◽  
High Degree ◽  
Y Family

ABSTRACT The Rev1 protein of Saccharomyces cerevisiae functions in translesion synthesis (TLS) together with DNA polymerase (Pol) ζ, which is comprised of the Rev3 catalytic and the Rev7 accessory subunits. Rev1, a member of the Y family of Pols, differs from other members in its high degree of specificity for incorporating a C opposite template G as well as opposite an abasic site. Although Rev1 is indispensable for Polζ-dependent TLS, its DNA synthetic activity is not required for many of the Polζ-dependent lesion bypass events. This observation has suggested a structural role for Rev1 in this process. Here we show that in yeast, Rev1 forms a stable complex with Rev7, and the two proteins copurify. Importantly, the polymerase-associated domain (PAD) of Rev1 mediates its binding to Rev7. These observations reveal a novel role for the PAD region of Rev1 in protein-protein interactions, and they raise the possibility of a similar involvement of the PAD of other Y family Pols in protein-protein interactions. We discuss the possible roles of Rev1 versus the Rev1-Rev7 complex in TLS.

scholarly journals Double-stranded DNA translocase activity of transcription factor TFIIH and the mechanism of RNA polymerase II open complex formation

2015 ◽  
Vol 112 (13) ◽  
pp. 3961-3966 ◽  
Author(s):  
James Fishburn ◽  
Eric Tomko ◽  
Eric Galburt ◽  
Steven Hahn
Keyword(s):  
Transcription Factor ◽  
Rna Polymerase ◽  
Rna Polymerase Ii ◽  
Transcription Initiation ◽  
Atp Hydrolysis ◽  
Dna Unwinding ◽  
Pol Ii ◽  
Torsional Strain ◽  
Double Stranded Dna ◽  
Dna Translocase

Formation of the RNA polymerase II (Pol II) open complex (OC) requires DNA unwinding mediated by the transcription factor TFIIH helicase-related subunit XPB/Ssl2. Because XPB/Ssl2 binds DNA downstream from the location of DNA unwinding, it cannot function using a conventional helicase mechanism. Here we show that yeast TFIIH contains an Ssl2-dependent double-stranded DNA translocase activity. Ssl2 tracks along one DNA strand in the 5′ → 3′ direction, implying it uses the nontemplate promoter strand to reel downstream DNA into the Pol II cleft, creating torsional strain and leading to DNA unwinding. Analysis of the Ssl2 and DNA-dependent ATPase activity of TFIIH suggests that Ssl2 has a processivity of approximately one DNA turn, consistent with the length of DNA unwound during transcription initiation. Our results can explain why maintaining the OC requires continuous ATP hydrolysis and the function of TFIIH in promoter escape. Our results also suggest that XPB/Ssl2 uses this translocase mechanism during DNA repair rather than physically wedging open damaged DNA.

scholarly journals OCT4 cooperates with distinct ATP-dependent chromatin remodelers in naïve and primed pluripotent states in human

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Xin Huang ◽  
Kyoung-mi Park ◽  
Paul Gontarz ◽  
Bo Zhang ◽  
Joshua Pan ◽  
...  
Keyword(s):  
Protein Interactions ◽  
Embryonic Stem ◽  
Chromatin Accessibility ◽  
Protein Protein Interactions ◽  
Human Escs ◽  
Nucleosome Remodeling ◽  
Chromatin Remodelers ◽  
Baf Complex ◽  
Common Transcription Factor ◽  
Optimal Maintenance

AbstractUnderstanding the molecular underpinnings of pluripotency is a prerequisite for optimal maintenance and application of embryonic stem cells (ESCs). While the protein-protein interactions of core pluripotency factors have been identified in mouse ESCs, their interactome in human ESCs (hESCs) has not to date been explored. Here we mapped the OCT4 interactomes in naïve and primed hESCs, revealing extensive connections to mammalian ATP-dependent nucleosome remodeling complexes. In naïve hESCs, OCT4 is associated with both BRG1 and BRM, the two paralog ATPases of the BAF complex. Genome-wide location analyses and genetic studies reveal that these two enzymes cooperate in a functionally redundant manner in the transcriptional regulation of blastocyst-specific genes. In contrast, in primed hESCs, OCT4 cooperates with BRG1 and SOX2 to promote chromatin accessibility at ectodermal genes. This work reveals how a common transcription factor utilizes differential BAF complexes to control distinct transcriptional programs in naïve and primed hESCs.

scholarly journals Structural basis of the XPB–Bax1 complex as a dynamic helicase–nuclease machinery for DNA repair

2020 ◽  
Vol 48 (11) ◽  
pp. 6326-6339 ◽  
Author(s):  
Kevin DuPrez ◽  
Feng He ◽  
Zhenhang Chen ◽  
Eduardo Hilario ◽  
Li Fan
Keyword(s):  
Dna Repair ◽  
Protein Interactions ◽  
Active Sites ◽  
Atp Hydrolysis ◽  
Excision Repair ◽  
Dna Lesions ◽  
Structural Basis ◽  
Protein Protein Interactions ◽  
Nucleotide Excision ◽  
First Time

Abstract Nucleotide excision repair (NER) is a major DNA repair pathway for a variety of DNA lesions. XPB plays a key role in DNA opening at damage sites and coordinating damage incision by nucleases. XPB is conserved from archaea to human. In archaea, XPB is associated with a nuclease Bax1. Here we report crystal structures of XPB in complex with Bax1 from Archaeoglobus fulgidus (Af) and Sulfolobus tokodaii (St). These structures reveal for the first time four domains in Bax1, which interacts with XPB mainly through its N-terminal domain. A Cas2-like domain likely helps to position Bax1 at the forked DNA allowing the nuclease domain to incise one arm of the fork. Bax1 exists in monomer or homodimer but forms a heterodimer exclusively with XPB. StBax1 keeps StXPB in a closed conformation and stimulates ATP hydrolysis by XPB while AfBax1 maintains AfXPB in the open conformation and reduces its ATPase activity. Bax1 contains two distinguished nuclease active sites to presumably incise DNA damage. Our results demonstrate that protein-protein interactions regulate the activities of XPB ATPase and Bax1 nuclease. These structures provide a platform to understand the XPB-nuclease interactions important for the coordination of DNA unwinding and damage incision in eukaryotic NER.

scholarly journals Molecular Dynamics of DNA Translocation by FtsK

2022 ◽  
Author(s):  
Joshua Pajak ◽  
Gaurav Arya
Keyword(s):  
Molecular Mechanisms ◽  
Atp Hydrolysis ◽  
Hydrolysis Product ◽  
Energy Landscapes ◽  
Dna Translocation ◽  
Product Release ◽  
Double Stranded Dna ◽  
A Subunit ◽  
Free Energy Landscapes ◽  
Compact Conformation

The bacterial FtsK motor harvests energy from ATP to translocate double-stranded DNA during cell division. Here, we probe the molecular mechanisms underlying coordinated DNA translocation in FtsK by performing long timescale simulations of its hexameric assembly and individual subunits. From these simulations we predict signaling pathways that connect the ATPase active site to DNA-gripping residues, which allows the motor to coordinate its translocation activity with its ATPase activity. Additionally, we utilize well-tempered metadynamics simulations to compute free-energy landscapes that elucidate the extended-to-compact transition involved in force generation. We show that nucleotide binding promotes a compact conformation of a motor subunit, whereas the apo subunit is flexible. Together, our results support a mechanism whereby each ATP-bound subunit of the motor conforms to the helical pitch of DNA, and ATP hydrolysis/product release causes a subunit to lose grip of DNA. By ordinally engaging and disengaging with DNA, the FtsK motor unidirectionally translocates DNA.

scholarly journals Targeting Chaperone/Co-Chaperone Interactions with Small Molecules: A Novel Approach to Tackle Neurodegenerative Diseases

Cells ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 2596
Author(s):  
Lisha Wang ◽  
Liza Bergkvist ◽  
Rajnish Kumar ◽  
Bengt Winblad ◽  
Pavel F. Pavlov
Keyword(s):  
Neurodegenerative Diseases ◽  
Small Molecules ◽  
Protein Interactions ◽  
Intracellular Transport ◽  
Atp Hydrolysis ◽  
Specific Protein ◽  
Future Perspective ◽  
Protein Protein Interactions ◽  
Novel Approach ◽  
Chaperone Interactions

The dysfunction of the proteostasis network is a molecular hallmark of neurodegenerative diseases such as Alzheimer’s disease, Parkinson’s disease, Huntington’s disease, and amyotrophic lateral sclerosis. Molecular chaperones are a major component of the proteostasis network and maintain cellular homeostasis by folding client proteins, assisting with intracellular transport, and interfering with protein aggregation or degradation. Heat shock protein 70 kDa (Hsp70) and 90 kDa (Hsp90) are two of the most important chaperones whose functions are dependent on ATP hydrolysis and collaboration with their co-chaperones. Numerous studies implicate Hsp70, Hsp90, and their co-chaperones in neurodegenerative diseases. Targeting the specific protein–protein interactions between chaperones and their particular partner co-chaperones with small molecules provides an opportunity to specifically modulate Hsp70 or Hsp90 function for neurodegenerative diseases. Here, we review the roles of co-chaperones in Hsp70 or Hsp90 chaperone cycles, the impacts of co-chaperones in neurodegenerative diseases, and the development of small molecules modulating chaperone/co-chaperone interactions. We also provide a future perspective of drug development targeting chaperone/co-chaperone interactions for neurodegenerative diseases.

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