scholarly journals Addressing the Molecular Mechanism of Longitudinal Lamin Assembly Using Chimeric Fusions

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1633 ◽  
Author(s):  
Giel Stalmans ◽  
Anastasia V. Lilina ◽  
Pieter-Jan Vermeire ◽  
Jan Fiala ◽  
Petr Novák ◽  
...  
Keyword(s):  
Cell Nucleus ◽  
Molecular Model ◽  
Coiled Coil ◽  
Cross Linking ◽  
Specific Interactions ◽  
Molecular Architecture ◽  
Filament Assembly ◽  
Assembly Mechanism ◽  
Recombinant Fragments ◽  
Chemical Cross Linking

The molecular architecture and assembly mechanism of intermediate filaments have been enigmatic for decades. Among those, lamin filaments are of particular interest due to their universal role in cell nucleus and numerous disease-related mutations. Filament assembly is driven by specific interactions of the elementary dimers, which consist of the central coiled-coil rod domain flanked by non-helical head and tail domains. We aimed to investigate the longitudinal ‘head-to-tail’ interaction of lamin dimers (the so-called ACN interaction), which is crucial for filament assembly. To this end, we prepared a series of recombinant fragments of human lamin A centred around the N- and C-termini of the rod. The fragments were stabilized by fusions to heterologous capping motifs which provide for a correct formation of parallel, in-register coiled-coil dimers. As a result, we established crystal structures of two N-terminal fragments one of which highlights the propensity of the coiled-coil to open up, and one C-terminal rod fragment. Additional studies highlighted the capacity of such N- and C-terminal fragments to form specific complexes in solution, which were further characterized using chemical cross-linking. These data yielded a molecular model of the ACN complex which features a 6.5 nm overlap of the rod ends.

scholarly journals Molecular Interactions Driving Intermediate Filament Assembly

Cells ◽  
2021 ◽  
Vol 10 (9) ◽  
pp. 2457
Author(s):  
Pieter-Jan Vermeire ◽  
Giel Stalmans ◽  
Anastasia V. Lilina ◽  
Jan Fiala ◽  
Petr Novak ◽  
...  
Keyword(s):  
Molecular Interactions ◽  
Coiled Coil ◽  
Structural Basis ◽  
Cross Linking ◽  
Cell Physiology ◽  
X Ray Crystallography ◽  
Filament Assembly ◽  
Open Questions ◽  
Near Future ◽  
Chemical Cross Linking

Given the role of intermediate filaments (IFs) in normal cell physiology and scores of IF-linked diseases, the importance of understanding their molecular structure is beyond doubt. Research into the IF structure was initiated more than 30 years ago, and some important advances have been made. Using crystallography and other methods, the central coiled-coil domain of the elementary dimer and also the structural basis of the soluble tetramer formation have been studied to atomic precision. However, the molecular interactions driving later stages of the filament assembly are still not fully understood. For cytoplasmic IFs, much of the currently available insight is due to chemical cross-linking experiments that date back to the 1990s. This technique has since been radically improved, and several groups have utilized it recently to obtain data on lamin filament assembly. Here, we will summarize these findings and reflect on the remaining open questions and challenges of IF structure. We argue that, in addition to X-ray crystallography, chemical cross-linking and cryoelectron microscopy are the techniques that should enable major new advances in the field in the near future.

Abstract 2225: The molecular architecture of p85α as determined by SAXS and chemical cross-linking.

2013 ◽  
Author(s):  
Evan T. Brower ◽  
Sandra B. Gabelli ◽  
Qing Wang ◽  
Raghothama Chaerkady ◽  
Christopher E. Berndsen ◽  
...  
Keyword(s):  
Cross Linking ◽  
Molecular Architecture ◽  
Chemical Cross Linking

scholarly journals Molecular Model of a Soluble Guanylyl Cyclase Fragment Determined by Small-Angle X-ray Scattering and Chemical Cross-Linking

Biochemistry ◽  
2013 ◽  
Vol 52 (9) ◽  
pp. 1568-1582 ◽  
Author(s):  
Bradley G. Fritz ◽  
Sue A. Roberts ◽  
Aqeel Ahmed ◽  
Linda Breci ◽  
Wenzhou Li ◽  
...  
Keyword(s):  
Guanylyl Cyclase ◽  
Small Angle ◽  
Molecular Model ◽  
Soluble Guanylyl Cyclase ◽  
Cross Linking ◽  
X Ray ◽  
X Ray Scattering ◽  
Chemical Cross Linking ◽  
Ray Scattering

scholarly journals Coronin Promotes the Rapid Assembly and Cross-linking of Actin Filaments and May Link the Actin and Microtubule Cytoskeletons in Yeast

1999 ◽  
Vol 144 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Bruce L. Goode ◽  
Jonathan J. Wong ◽  
Anne-Christine Butty ◽  
Matthias Peter ◽  
Ashley L. McCormack ◽  
...  
Keyword(s):  
Actin Filaments ◽  
Coiled Coil ◽  
Cross Linking ◽  
Cortical Actin ◽  
Functional Link ◽  
Microtubule Binding ◽  
Filament Assembly ◽  
Cell Extracts ◽  
Cross Links

Coronin is a highly conserved actin-associated protein that until now has had unknown biochemical activities. Using microtubule affinity chromatography, we coisolated actin and a homologue of coronin, Crn1p, from Saccharomyces cerevisiae cell extracts. Crn1p is an abundant component of the cortical actin cytoskeleton and binds to F-actin with high affinity (Kd 6 × 10−9 M). Crn1p promotes the rapid barbed-end assembly of actin filaments and cross-links filaments into bundles and more complex networks, but does not stabilize them. Genetic analyses with a crn1Δ deletion mutation also are consistent with Crn1p regulating filament assembly rather than stability. Filament cross-linking depends on the coiled coil domain of Crn1p, suggesting a requirement for Crn1p dimerization. Assembly-promoting activity is independent of cross-linking and could be due to nucleation and/or accelerated polymerization. Crn1p also binds to microtubules in vitro, and microtubule binding is enhanced by the presence of actin filaments. Microtubule binding is mediated by a region of Crn1p that contains sequences (not found in other coronins) homologous to the microtubule binding region of MAP1B. These activities, considered with microtubule defects observed in crn1Δ cells and in cells overexpressing Crn1p, suggest that Crn1p may provide a functional link between the actin and microtubule cytoskeletons in yeast.

scholarly journals Molecular Architecture of Photoreceptor Phosphodiesterase Elucidated by Chemical Cross-Linking and Integrative Modeling

2014 ◽  
Vol 426 (22) ◽  
pp. 3713-3728 ◽  
Author(s):  
Xiaohui Zeng-Elmore ◽  
Xiong-Zhuo Gao ◽  
Riccardo Pellarin ◽  
Dina Schneidman-Duhovny ◽  
Xiu-Jun Zhang ◽  
...  
Keyword(s):  
Cross Linking ◽  
Molecular Architecture ◽  
Integrative Modeling ◽  
Photoreceptor Phosphodiesterase ◽  
Chemical Cross Linking

scholarly journals A molecular model for self-assembly of synaptonemal complex protein SYCE3

2019 ◽  
Author(s):  
Orla M Dunne ◽  
Owen R Davies
Keyword(s):  
Synaptonemal Complex ◽  
Self Assembly ◽  
Homologous Chromosome ◽  
Molecular Model ◽  
Three Dimensional ◽  
Coiled Coil ◽  
Central Element ◽  
Domain Swap ◽  
Assembly Mechanism ◽  
Four Helical Bundle

The synaptonemal complex (SC) is a supramolecular protein assembly that mediates homologous chromosome synapsis during meiosis. This zipper-like structure assembles in a continuous manner between homologous chromosome axes, enforcing a 100-nm separation along their entire length, and providing the necessary three-dimensional framework for crossover formation. The mammalian SC is formed of eight components - SYCP1-3, SYCE1-3, TEX12 and SIX6OS1 - arranged in transverse and longitudinal structures. These largely α-helical coiled-coil proteins undergo heterotypic interactions, coupled with recursive self-assembly of SYCP1, SYCE2-TEX12, and SYCP2-SYCP3, to achieve the vast supramolecular structure of the SC. Here, we report a novel self-assembly mechanism of SC central element component SYCE3, identified through multi-angle light scattering and small-angle X-ray scattering. SYCE3 adopts a dimeric four-helical bundle structure that acts as the building block for concentration-dependent self-assembly into a series of discrete higher order oligomers. This is achieved through staggered lateral interactions between self-assembly surfaces of SYCE3 dimers, and their end-on interaction through intermolecular domain-swap between dimer folds. These mechanisms combine to achieve potentially limitless SYCE3 assembly, which particularly favours formation of dodecamers of three laterally associated domain-swap tetramers. Our findings extend the family of self-assembling proteins within the SC and provide novel means for structural stabilisation of the SC central element.

Specific interactions of the alkali light chain 1 in skeletal myosin heads probed by chemical cross-linking

Biochemistry ◽  
1986 ◽  
Vol 25 (25) ◽  
pp. 8325-8330 ◽  
Author(s):  
Jean Pierre Labbe ◽  
Etienne Audemard ◽  
Raoul Bertrand ◽  
Ridha Kassab
Keyword(s):  
Light Chain ◽  
Cross Linking ◽  
Specific Interactions ◽  
Skeletal Myosin ◽  
Chemical Cross Linking

scholarly journals Molecular Architecture of the Bardet-Biedl Syndrome Protein 2-7-9 Subcomplex

2019 ◽  
Author(s):  
W. Grant Ludlam ◽  
Takuma Aoba ◽  
Jorge Cuéllar ◽  
M. Teresa Bueno-Carrasco ◽  
Aman Makaju ◽  
...  
Keyword(s):  
Genetic Disease ◽  
Molecular Basis ◽  
Primary Cilia ◽  
Molecular Model ◽  
Coiled Coil ◽  
Chemical Crosslinking ◽  
Molecular Architecture ◽  
Bardet Biedl Syndrome ◽  
Helical Domain ◽  
Syndrome Protein

SummaryBardet-Biedl syndrome (BBS) is a genetic disease caused by mutations that disrupt the function of the BBSome, an eight-subunit complex that plays an important role in transport of proteins in primary cilia. To better understand the molecular basis of the disease, we analyzed the structure of a BBSome subcomplex consisting of three homologous BBS proteins (BBS2, BBS7, and BBS9) by an integrative structural modeling approach using electron microscopy and chemical crosslinking coupled with mass spectrometry. The resulting molecular model revealed an overall structure that resembles a flattened triangle. Within the structure, BBS2 and BBS7 form a tight dimer based on a coiled-coil interaction, and BBS9 associates with the dimer via an interaction with the α-helical domain of BBS2. Interestingly, a BBS-linked mutation of BBS2 (R632P) is located in the α-helical domain at the interface between BBS2 and BBS9, and binding experiments showed that this mutation disrupted the interaction of BBS2 with BBS9. This finding suggests that BBSome assembly is disrupted by the R632P substitution, providing a molecular explanation for BBS in patients harboring this mutation.

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

Sign in / Sign up

Export Citation Format

Share Document