Mouse MORC3 is a GHKL ATPase that localizes to H3K4me3 marked chromatin

Microrchidia (MORC) proteins are GHKL (gyrase, heat-shock protein 90, histidine kinase, MutL) ATPases that function in gene regulation in multiple organisms. Animal MORCs also contain CW-type zinc finger domains, which are known to bind to modified histones. We solved the crystal structure of the murine MORC3 ATPase-CW domain bound to the nucleotide analog AMPPNP (phosphoaminophosphonic acid-adenylate ester) and in complex with a trimethylated histone H3 lysine 4 (H3K4) peptide (H3K4me3). We observed that the MORC3 N-terminal ATPase domain forms a dimer when bound to AMPPNP. We used native mass spectrometry to show that dimerization is ATP-dependent, and that dimer formation is enhanced in the presence of nonhydrolyzable ATP analogs. The CW domain uses an aromatic cage to bind trimethylated Lys4 and forms extensive hydrogen bonds with the H3 tail. We found that MORC3 localizes to promoters marked by H3K4me3 throughout the genome, consistent with its binding to H3K4me3 in vitro. Our work sheds light on aspects of the molecular dynamics and function of MORC3.

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The function and dynamics of the apical scaffolding protein E3KARP are regulated by cell-cycle phosphorylation

Molecular Biology of the Cell ◽

10.1091/mbc.e15-07-0498 ◽

2015 ◽

Vol 26 (20) ◽

pp. 3615-3627 ◽

Cited By ~ 1

Author(s):

Cécile Sauvanet ◽

Damien Garbett ◽

Anthony Bretscher

Keyword(s):

Pdz Domain ◽

Duplication Event ◽

Scaffolding Protein ◽

Gene Duplication Event ◽

Pdz Domains ◽

Tail Region ◽

Dynamics And Function ◽

And Function

We examine the dynamics and function of the apical scaffolding protein E3KARP/NHERF2, which consists of two PDZ domains and a tail containing an ezrin-binding domain. The exchange rate of E3KARP is greatly enhanced during mitosis due to phosphorylation at Ser-303 in its tail region. Whereas E3KARP can substitute for the function of the closely related scaffolding protein EBP50/NHERF1 in the formation of interphase microvilli, E3KARP S303D cannot. Moreover, the S303D mutation enhances the in vivo dynamics of the E3KARP tail alone, whereas in vitro the interaction of E3KARP with active ezrin is unaffected by S303D, implicating another factor regulating dynamics in vivo. A-Raf is found to be required for S303 phosphorylation in mitotic cells. Regulation of the dynamics of EBP50 is known to be dependent on its tail region but modulated by PDZ domain occupancy, which is not the case for E3KARP. Of interest, in both cases, the mechanisms regulating dynamics involve the tails, which are the most diverged region of the paralogues and probably evolved independently after a gene duplication event that occurred early in vertebrate evolution.

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Lipid Membrane Mimetics in Functional and Structural Studies of Integral Membrane Proteins

Membranes ◽

10.3390/membranes11090685 ◽

2021 ◽

Vol 11 (9) ◽

pp. 685

Author(s):

Saman Majeed ◽

Akram Bani Ahmad ◽

Ujala Sehar ◽

Elka R. Georgieva

Keyword(s):

Membrane Proteins ◽

Lipid Membrane ◽

Physiological State ◽

Integral Membrane Proteins ◽

Membrane Properties ◽

Protein Activity ◽

Functional Studies ◽

Dynamics And Function ◽

And Function

Integral membrane proteins (IMPs) fulfill important physiological functions by providing cell–environment, cell–cell and virus–host communication; nutrients intake; export of toxic compounds out of cells; and more. However, some IMPs have obliterated functions due to polypeptide mutations, modifications in membrane properties and/or other environmental factors—resulting in damaged binding to ligands and the adoption of non-physiological conformations that prevent the protein from returning to its physiological state. Thus, elucidating IMPs’ mechanisms of function and malfunction at the molecular level is important for enhancing our understanding of cell and organism physiology. This understanding also helps pharmaceutical developments for restoring or inhibiting protein activity. To this end, in vitro studies provide invaluable information about IMPs’ structure and the relation between structural dynamics and function. Typically, these studies are conducted on transferred from native membranes to membrane-mimicking nano-platforms (membrane mimetics) purified IMPs. Here, we review the most widely used membrane mimetics in structural and functional studies of IMPs. These membrane mimetics are detergents, liposomes, bicelles, nanodiscs/Lipodisqs, amphipols, and lipidic cubic phases. We also discuss the protocols for IMPs reconstitution in membrane mimetics as well as the applicability of these membrane mimetic-IMP complexes in studies via a variety of biochemical, biophysical, and structural biology techniques.

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STRUCTURE, DYNAMICS, AND FUNCTION OF CHROMATIN IN VITRO

Annual Review of Biophysics and Biomolecular Structure ◽

10.1146/annurev.biophys.27.1.285 ◽

1998 ◽

Vol 27 (1) ◽

pp. 285-327 ◽

Cited By ~ 192

Author(s):

J. Widom

Keyword(s):

Structure Dynamics ◽

Dynamics And Function ◽

And Function

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Structure of human collapsin response mediator protein 1: a possible role of its C-terminal tail

Acta Crystallographica Section F Structural Biology Communications ◽

10.1107/s2053230x15009243 ◽

2015 ◽

Vol 71 (8) ◽

pp. 938-945 ◽

Cited By ~ 3

Author(s):

Szu-Heng Liu ◽

Shih-Fang Huang ◽

Yuan-Ling Hsu ◽

Szu-Hua Pan ◽

Yen-Ju Chen ◽

...

Keyword(s):

Crystal Structure ◽

Structural Changes ◽

Collapsin Response Mediator Protein ◽

Mediator Protein ◽

Dynamics And Function ◽

And Function ◽

Tetrameric Assembly

Collapsin response mediator protein 1 (CRMP-1) is the first identified member of the CRMP family and is crucial for both the mediation of neuronal differentiation and in suppressing the invasion of lung cancer. The crystal structure of full-length human CRMP-1 was determined at a resolution of 3 Å. Human CRMP-1 comprises a tetrameric assembly; its overall structure is similar to that of mouse CRMP-1, but the measured electron density of the C-terminal residues 488–496 show a randomly coiled link that connects the protomers to each other, within which residues 497–572 are proteolytically susceptiblein vivo. Deletion of residues 472–572 by thrombinin vitronot only releases a randomly coiled tail but also transduces observable structural changes of CRMP-1, as revealed by analytical size-exclusive chromatography and circular dichroism spectra. These results indicate a possible alternative role in CRMP dynamics and function.

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Molecular architecture and functions of the neuronal cytoskeleton

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100157541 ◽

1990 ◽

Vol 48 (3) ◽

pp. 2-3

Author(s):

Nobutaka Hirokawa

Keyword(s):

Major Elements ◽

Molecular Structures ◽

Organelle Transport ◽

Molecular Architecture ◽

Neuronal Morphogenesis ◽

Microtubule Associated Proteins ◽

Associated Proteins ◽

And Function ◽

Small Clusters

In this symposium I will present our studies about the molecular architecture and function of the cytomatrix of the nerve cells. The nerve cell is a highly polarized cell composed of highly branched dendrites, cell body, and a single long axon along the direction of the impulse propagation. Each part of the neuron takes characteristic shapes for which the cytoskeleton provides the framework. The neuronal cytoskeletons play important roles on neuronal morphogenesis, organelle transport and the synaptic transmission. In the axon neurofilaments (NF) form dense arrays, while microtubules (MT) are arranged as small clusters among the NFs. On the other hand, MTs are distributed uniformly, whereas NFs tend to run solitarily or form small fascicles in the dendrites Quick freeze deep etch electron microscopy revealed various kinds of strands among MTs, NFs and membranous organelles (MO). These structures form major elements of the cytomatrix in the neuron. To investigate molecular nature and function of these filaments first we studied molecular structures of microtubule associated proteins (MAP1A, MAP1B, MAP2, MAP2C and tau), and microtubules reconstituted from MAPs and tubulin in vitro. These MAPs were all fibrous molecules with different length and formed arm like projections from the microtubule surface.

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Decision letter for "Human monocytic myeloid‐derived suppressor cells impair B‐cell phenotype and function in vitro"

10.1002/eji.201948240/v2/decision1 ◽

2019 ◽

Keyword(s):

B Cell ◽

Suppressor Cells ◽

Cell Phenotype ◽

Myeloid Derived Suppressor Cells ◽

And Function

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Review for "Human monocytic myeloid‐derived suppressor cells impair B‐cell phenotype and function in vitro"

10.1002/eji.201948240/v1/review1 ◽

2019 ◽

Keyword(s):

B Cell ◽

Suppressor Cells ◽

Cell Phenotype ◽

Myeloid Derived Suppressor Cells ◽

And Function

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Role of the 807 C/T Polymorphism of the α2 Gene in Platelet GP Ia Collagen Receptor Expression and Function

Thrombosis and Haemostasis ◽

10.1055/s-0037-1614605 ◽

1999 ◽

Vol 81 (06) ◽

pp. 951-956 ◽

Cited By ~ 59

Author(s):

J. Corral ◽

R. González-Conejero ◽

J. Rivera ◽

F. Ortuño ◽

P. Aparicio ◽

...

Keyword(s):

Venous Thrombosis ◽

Cell Types ◽

Receptor Expression ◽

Case Control Studies ◽

Platelet Surface ◽

Vitro Analysis ◽

And Function ◽

In Vitro Analysis

SummaryThe variability of the platelet GP Ia/IIa density has been associated with the 807 C/T polymorphism (Phe 224) of the GP Ia gene in American Caucasian population. We have investigated the genotype and allelic frequencies of this polymorphism in Spanish Caucasians. The T allele was found in 35% of the 284 blood donors analyzed. We confirmed in 159 healthy subjects a significant association between the 807 C/T polymorphism and the platelet GP Ia density. The T allele correlated with high number of GP Ia molecules on platelet surface. In addition, we observed a similar association of this polymorphism with the expression of this protein in other blood cell types. The platelet responsiveness to collagen was determined by “in vitro” analysis of the platelet activation and aggregation response. We found no significant differences in these functional platelet parameters according to the 807 C/T genotype. Finally, results from 3 case/control studies involving 302 consecutive patients (101 with coronary heart disease, 104 with cerebrovascular disease and 97 with deep venous thrombosis) determined that the 807 C/T polymorphism of the GP Ia gene does not represent a risk factor for arterial or venous thrombosis.

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