scholarly journals Afadin: A Novel Actin Filament–binding Protein with One PDZ Domain Localized at Cadherin-based Cell-to-Cell Adherens Junction

1997 ◽  
Vol 139 (2) ◽  
pp. 517-528 ◽  
Author(s):  
Kenji Mandai ◽  
Hiroyuki Nakanishi ◽  
Ayako Satoh ◽  
Hiroshi Obaishi ◽  
Manabu Wada ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Rat Brain ◽  
Actin Filament ◽  
Pdz Domain ◽  
Adherens Junction ◽  
Binding Domain ◽  
Actin Binding ◽  
Calculated Molecular Mass ◽  
Splicing Variant ◽  
Actin Binding Domain

A novel actin filament (F-actin)–binding protein with a molecular mass of ∼205 kD (p205), which was concentrated at cadherin-based cell-to-cell adherens junction (AJ), was isolated and characterized. p205 was purified from rat brain and its cDNA was cloned from a rat brain cDNA library. p205 was a protein of 1,829 amino acids (aa) with a calculated molecular mass of 207,667 kD. p205 had one F-actin–binding domain at 1,631–1,829 aa residues and one PDZ domain at 1,016– 1,100 aa residues, a domain known to interact with transmembrane proteins. p205 was copurified from rat brain with another protein with a molecular mass of 190 kD (p190). p190 was a protein of 1,663 aa with a calculated molecular mass of 188,971 kD. p190 was a splicing variant of p205 having one PDZ domain at 1,009–1,093 aa residues but lacking the F-actin–binding domain. Homology search analysis revealed that the aa sequence of p190 showed 90% identity over the entire sequence with the product of the AF-6 gene, which was found to be fused to the ALL-1 gene, known to be involved in acute leukemia. p190 is likely to be a rat counterpart of human AF-6 protein. p205 bound along the sides of F-actin but hardly showed the F-actin–cross-linking activity. Northern and Western blot analyses showed that p205 was ubiquitously expressed in all the rat tissues examined, whereas p190 was specifically expressed in brain. Immunofluorescence and immunoelectron microscopic studies revealed that p205 was concentrated at cadherin-based cell-to-cell AJ of various tissues. We named p205 l-afadin (a large splicing variant of AF-6 protein localized at adherens junction) and p190 s-afadin (a small splicing variant of l-afadin). These results suggest that l-afadin serves as a linker of the actin cytoskeleton to the plasma membrane at cell-to-cell AJ.

scholarly journals αE-catenin actin-binding domain alters actin filament conformation and regulates binding of nucleation and disassembly factors

2013 ◽  
Vol 24 (23) ◽  
pp. 3710-3720 ◽  
Author(s):  
Scott D. Hansen ◽  
Adam V. Kwiatkowski ◽  
Chung-Yueh Ouyang ◽  
HongJun Liu ◽  
Sabine Pokutta ◽  
...  
Keyword(s):  
Actin Filament ◽  
Actin Filaments ◽  
Binding Domain ◽  
Actin Binding ◽  
Filamentous Actin ◽  
Filament Structure ◽  
Actin Binding Domain ◽  
Filament Bundles ◽  
Underlying Mechanisms ◽  
Cell Cell

The actin-binding protein αE-catenin may contribute to transitions between cell migration and cell–cell adhesion that depend on remodeling the actin cytoskeleton, but the underlying mechanisms are unknown. We show that the αE-catenin actin-binding domain (ABD) binds cooperatively to individual actin filaments and that binding is accompanied by a conformational change in the actin protomer that affects filament structure. αE-catenin ABD binding limits barbed-end growth, especially in actin filament bundles. αE-catenin ABD inhibits actin filament branching by the Arp2/3 complex and severing by cofilin, both of which contact regions of the actin protomer that are structurally altered by αE-catenin ABD binding. In epithelial cells, there is little correlation between the distribution of αE-catenin and the Arp2/3 complex at developing cell–cell contacts. Our results indicate that αE-catenin binding to filamentous actin favors assembly of unbranched filament bundles that are protected from severing over more dynamic, branched filament arrays.

The actin-binding domain of actin filament-associated protein (AFAP) is involved in the regulation of cytoskeletal structure

2011 ◽  
Vol 69 (7) ◽  
pp. 1137-1151 ◽  
Author(s):  
Helan Xiao ◽  
Bing Han ◽  
Monika Lodyga ◽  
Xiao-Hui Bai ◽  
Yingchun Wang ◽  
...  
Keyword(s):  
Actin Filament ◽  
Binding Domain ◽  
Actin Binding ◽  
Cytoskeletal Structure ◽  
Actin Binding Domain

scholarly journals Force-dependent allostery of the α-catenin actin-binding domain controls adherens junction dynamics and functions

2018 ◽  
Vol 9 (1) ◽  
Author(s):  
Noboru Ishiyama ◽  
Ritu Sarpal ◽  
Megan N. Wood ◽  
Samantha K. Barrick ◽  
Tadateru Nishikawa ◽  
...  
Keyword(s):  
Adherens Junction ◽  
Binding Domain ◽  
Actin Binding ◽  
Actin Binding Domain

scholarly journals Nexilin: A Novel Actin Filament-binding Protein Localized at Cell–Matrix Adherens Junction

1998 ◽  
Vol 143 (5) ◽  
pp. 1227-1238 ◽  
Author(s):  
Toshihisa Ohtsuka ◽  
Hiroyuki Nakanishi ◽  
Wataru Ikeda ◽  
Ayako Satoh ◽  
Yumiko Momose ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Rat Brain ◽  
Actin Filament ◽  
Binding Protein ◽  
Adherens Junction ◽  
Actin Binding ◽  
Calculated Molecular Weight ◽  
Cell Matrix ◽  
Focal Contacts ◽  
Cell Cell

We isolated two novel actin filament (F-actin)–binding proteins from rat brain and rat 3Y1 fibroblast. They were splicing variants, and we named brain big one b-nexilin and fibroblast small one s-nexilin. b-Nexilin purified from rat brain was a protein of 656 amino acids (aa) with a calculated molecular weight of 78,392, whereas s-nexilin, encoded by the cDNA isolated from rat 3Y1 cells by the reverse transcriptase-PCR method, was a protein of 606 aa with a calculated molecular weight of 71,942. b-Nexilin had two F-actin– binding domains (ABDs) at the NH2-terminal and middle regions, whereas s-nexilin had one ABD at the middle region because 64 aa residues were deleted and 14 aa residues were inserted in the first NH2-terminal ABD of b-nexilin, and thereby the first ABD lost its activity. b- and s-nexilins bound along the sides of F-actin, but only b-nexilin showed F-actin cross-linking activity. b-Nexilin was mainly expressed in brain and testis, whereas s-nexilin was mainly expressed in testis, spleen, and fibroblasts, such as rat 3Y1 and mouse Swiss 3T3 cells, but neither b- nor s-nexilin was detected in liver, kidney, or cultured epithelial cells. An immunofluorescence microscopic study revealed that s-nexilin was colocalized with vinculin, talin, and paxillin at cell– matrix adherens junction (AJ) and focal contacts, but not at cell–cell AJ, in 3Y1 cells. Overexpressed b- and s-nexilins were localized at focal contacts but not at cell–cell AJ. These results indicate that nexilin is a novel F-actin–binding protein localized at cell–matrix AJ.

scholarly journals Neurabin: A Novel Neural Tissue–specific Actin Filament–binding Protein Involved in Neurite Formation

1997 ◽  
Vol 139 (4) ◽  
pp. 951-961 ◽  
Author(s):  
Hiroyuki Nakanishi ◽  
Hiroshi Obaishi ◽  
Ayako Satoh ◽  
Manabu Wada ◽  
Kenji Mandai ◽  
...  
Keyword(s):  
Rat Brain ◽  
Actin Filament ◽  
Binding Protein ◽  
Neural Tissue ◽  
Terminal Region ◽  
Actin Binding ◽  
Calculated Molecular Mass ◽  
Tissue Specific ◽  
Actin Binding Protein ◽  
Neurite Formation

We purified from rat brain a novel actin filament (F-actin)–binding protein of ∼180 kD (p180), which was specifically expressed in neural tissue. We named p180 neurabin (neural tissue–specific F-actin– binding protein). We moreover cloned the cDNA of neurabin from a rat brain cDNA library and characterized native and recombinant proteins. Neurabin was a protein of 1,095 amino acids with a calculated molecular mass of 122,729. Neurabin had one F-actin–binding domain at the NH2-terminal region, one PSD-95, DlgA, ZO-1–like domain at the middle region, a domain known to interact with transmembrane proteins, and domains predicted to form coiled-coil structures at the COOH-terminal region. Neurabin bound along the sides of F-actin and showed F-actin–cross-linking activity. Immunofluorescence microscopic analysis revealed that neurabin was highly concentrated in the synapse of the developed neurons. Neurabin was also concentrated in the lamellipodia of the growth cone during the development of neurons. Moreover, a study on suppression of endogenous neurabin in primary cultured rat hippocampal neurons by treatment with an antisense oligonucleotide showed that neurabin was involved in the neurite formation. Neurabin is a candidate for key molecules in the synapse formation and function.

scholarly journals Binding to F-actin guides cadherin cluster assembly, stability, and movement

2013 ◽  
Vol 201 (1) ◽  
pp. 131-143 ◽  
Author(s):  
Soonjin Hong ◽  
Regina B. Troyanovsky ◽  
Sergey M. Troyanovsky
Keyword(s):  
Adherens Junction ◽  
Random Motion ◽  
Binding Domain ◽  
Actin Binding ◽  
Cluster Assembly ◽  
Structural Elements ◽  
Binding Interface ◽  
Extracellular Region ◽  
Actin Binding Domain ◽  
Intracellular Binding

The cadherin extracellular region produces intercellular adhesion clusters through trans- and cis-intercadherin bonds, and the intracellular region connects these clusters to the cytoskeleton. To elucidate the interdependence of these binding events, cadherin adhesion was reconstructed from the minimal number of structural elements. F-actin–uncoupled adhesive clusters displayed high instability and random motion. Their assembly required a cadherin cis-binding interface. Coupling these clusters with F-actin through an α-catenin actin-binding domain (αABD) dramatically extended cluster lifetime and conferred direction to cluster motility. In addition, αABD partially lifted the requirement for the cis-interface for cluster assembly. Even more dramatic enhancement of cadherin clustering was observed if αABD was joined with cadherin through a flexible linker or if it was replaced with an actin-binding domain of utrophin. These data present direct evidence that binding to F-actin stabilizes cadherin clusters and cooperates with the cis-interface in cadherin clustering. Such cooperation apparently synchronizes extracellular and intracellular binding events in the process of adherens junction assembly.

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