scholarly journals Kinectin-dependent ER transport supports the focal complex maturation required for chemotaxis in shallow gradients

2016 ◽  
Vol 129 (13) ◽  
pp. 2660-2672
Author(s):  
Inn Chuan Ng ◽  
Pornteera Pawijit ◽  
Lee Ying Teo ◽  
Huipeng Li ◽  
Shu Ying Lee ◽  
...  
Keyword(s):  
Focal Complex

Role of the β1-integrin cytoplasmic tail in mediating invasin-promoted internalization of Yersinia

2002 ◽  
Vol 115 (13) ◽  
pp. 2669-2678 ◽  
Author(s):  
Anna Gustavsson ◽  
Annika Armulik ◽  
Cord Brakebusch ◽  
Reinhard Fässler ◽  
Staffan Johansson ◽  
...  
Keyword(s):  
Marked Reduction ◽  
Yersinia Pseudotuberculosis ◽  
Host Cells ◽  
Β1 Integrin ◽  
Complex Structures ◽  
Wild Type ◽  
Similar Reduction ◽  
Focal Complex ◽  
Β1 Integrins

Invasin of Yersinia pseudotuberculosis binds to β1-integrins on host cells and triggers internalization of the bacterium. To elucidate the mechanism behind the β1-integrin-mediated internalization of Yersinia, a β1-integrin-deficient cell line, GD25, transfected with wild-type β1A, β1B or different mutants of the β1A subunit was used. Both β1A and β1B bound to invasin-expressing bacteria, but only β1A was able to mediate internalization of the bacteria. The cytoplasmic region of β1A, differing from β1B, contains two NPXY motifs surrounding a double threonine site. Exchanging the tyrosines of the two NPXYs to phenylalanines did not inhibit the uptake, whereas a marked reduction was seen when the first tyrosine (Y783) was exchanged to alanine. A similar reduction was seen when the two nearby threonines (TT788-9) were exchanged with alanines. It was also noted that cells affected in bacterial internalization exhibited reduced spreading capability when seeded onto invasin, suggesting a correlation between the internalization of invasin-expressing bacteria and invasin-induced spreading. Likewise, integrins defective in forming peripheral focal complex structures was unable to mediate uptake of invasin-expressing bacteria.

scholarly journals The assembly of integrin adhesion complexes requires both extracellular matrix and intracellular rho/rac GTPases.

1995 ◽  
Vol 131 (6) ◽  
pp. 1857-1865 ◽  
Author(s):  
N A Hotchin ◽  
A Hall
Keyword(s):  
Extracellular Matrix ◽  
Growth Factors ◽  
Complex Formation ◽  
Map Kinase ◽  
Human Fibroblasts ◽  
Focal Adhesions ◽  
Small Gtpases ◽  
Wide Range ◽  
Focal Complex ◽  
Rho Family

Interaction of cells with extracellular matrix via integrin adhesion receptors plays an important role in a wide range of cellular: functions, for example cell growth, movement, and differentiation. Upon interaction with substrate, integrins cluster and associate with a variety of cytoplasmic proteins to form focal complexes and with the actin cytoskeleton. Although the intracellular signals induced by integrins are at present undefined, it is thought that they are mediated by proteins recruited to the focal complexes. It has been suggested, for example, that after recruitment to focal adhesions p125FAK can activate the ERK1/2 MAP kinase cascade. We have previously reported that members of the rho family of small GTPases can trigger the assembly of focal complexes when activated in cells. Using microinjection techniques, we have now examined the role of the extracellular matrix and of the two GTP-binding proteins, rac and rho, in the assembly of integrin complexes in both mouse and human fibroblasts. We find that the interaction of integrins with extracellular matrix alone is not sufficient to induce integrin clustering and focal complex formation. Similarly, activation of rho or rac by extracellular growth factors does not lead to focal complex formation in the absence of matrix. Focal complexes are only assembled in the presence of both matrix and functionally active members of the rho family. In agreement with this, the interaction of integrins with matrix in the absence of rho/rac activity is unable to activate the ERK1/2 kinases in Swiss 3T3 cells. In fact, ERK1/2 can be activated fully by growth factors in the absence of matrix and it seems unlikely, therefore, that the adhesion dependence of fibroblast growth is mediated through the ras/MAP kinase pathway. We conclude that extracellular matrix is not sufficient to trigger focal complex assembly and subsequent integrin-dependent signal transduction in the absence of functionally active members of the rho family of GTPases.

scholarly journals Integrin Activation and Focal Complex Formation in Cardiac Hypertrophy

2000 ◽  
Vol 275 (45) ◽  
pp. 35624-35630 ◽  
Author(s):  
Martin Laser ◽  
Christopher D. Willey ◽  
Wenjing Jiang ◽  
George Cooper ◽  
Donald R. Menick ◽  
...  
Keyword(s):  
Complex Formation ◽  
Cardiac Hypertrophy ◽  
Integrin Activation ◽  
Focal Complex

scholarly journals Tropomyosin Isoform Expression Regulates the Transition of Adhesions To Determine Cell Speed and Direction

2009 ◽  
Vol 29 (6) ◽  
pp. 1506-1514 ◽  
Author(s):  
Cuc T. T. Bach ◽  
Sarah Creed ◽  
Jessie Zhong ◽  
Maha Mahmassani ◽  
Galina Schevzov ◽  
...  
Keyword(s):  
Focal Adhesion ◽  
Actin Filaments ◽  
Feedback Loop ◽  
Cell Movement ◽  
Focal Adhesions ◽  
Leading Edge ◽  
Mesenchymal Cell ◽  
Critical Determinant ◽  
Focal Complex

ABSTRACT The balance of transition between distinct adhesion types contributes to the regulation of mesenchymal cell migration, and the characteristic association of adhesions with actin filaments led us to question the role of actin filament-associating proteins in the transition between adhesive states. Tropomyosin isoform association with actin filaments imparts distinct filament structures, and we have thus investigated the role for tropomyosins in determining the formation of distinct adhesion structures. Using combinations of overexpression, knockdown, and knockout approaches, we establish that Tm5NM1 preferentially stabilizes focal adhesions and drives the transition to fibrillar adhesions via stabilization of actin filaments. Moreover, our data suggest that the expression of Tm5NM1 is a critical determinant of paxillin phosphorylation, a signaling event that is necessary for focal adhesion disassembly. Thus, we propose that Tm5NM1 can regulate the feedback loop between focal adhesion disassembly and focal complex formation at the leading edge that is required for productive and directed cell movement.

TGFβ-induced focal complex formation in epithelial cells is mediated by activated ERK and JNK MAP kinases and is independent of Smad4

2005 ◽  
Vol 386 (3) ◽  
Author(s):  
Yukiko Imamichi ◽  
Oliver Waidmann ◽  
Ramona Hein ◽  
Pinelopi Eleftheriou ◽  
Klaudia Giehl ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Complex Formation ◽  
Map Kinases ◽  
Focal Complex

MEGAP impedes cell migration via regulating actin and microtubule dynamics and focal complex formation

2006 ◽  
Vol 312 (12) ◽  
pp. 2379-2393 ◽  
Author(s):  
Ying Yang ◽  
Marco Marcello ◽  
Volker Endris ◽  
Rainer Saffrich ◽  
Roger Fischer ◽  
...  
Keyword(s):  
Cell Migration ◽  
Complex Formation ◽  
Microtubule Dynamics ◽  
Focal Complex

Multifaceted Nano- and Micropatterned Surfaces for Cell Adhesion Manipulation

2010 ◽  
Author(s):  
John H. Slater ◽  
Jordan S. Miller ◽  
Shann S. Yu ◽  
Jennifer L. West
Keyword(s):  
Cell Biology ◽  
Soft Lithography ◽  
Microcontact Printing ◽  
Focal Adhesions ◽  
Site Formation ◽  
Cell Behavior ◽  
Ligand Type ◽  
Focal Complex ◽  
Cell Surface Interactions ◽  
Adhesion Site

Surfaces displaying nano- and micropatterned cell adhesive ligands have led to numerous discoveries in cell biology. Soft lithography techniques such as microcontact printing are well suited for creating surfaces displaying micropatterns of one ligand type in a single arrangement but are difficult to implement for the creation of multifaceted surfaces that present multiple ligand types with each ligand confined to their own pattern. To better understand the influence of extracellular matrix (ECM) composition on adhesion site formation and gross cell behavior (motility, proliferation, differentiation, etc.) it would be advantageous to posses the ability to create surfaces displaying multiple patterned ligands with length scales ranging from < 0.25 μm2, the typical size of a focal complex to > 1 μm2, the size of focal adhesions. Higher spatial resolution than what is easily achieved with microcontact printing is also desired. Such surfaces would allow for the simultaneous investigations of adhesion site maturation and composition and how changes in these properties can be implemented to engineer cell behavior via cell-surface interactions.

scholarly journals Myosin II directly binds and inhibits Dbl family guanine nucleotide exchange factors: a possible link to Rho family GTPases

2010 ◽  
Vol 190 (4) ◽  
pp. 663-674 ◽  
Author(s):  
Chan-Soo Lee ◽  
Chang-Ki Choi ◽  
Eun-Young Shin ◽  
Martin Alexander Schwartz ◽  
Eung-Gook Kim
Keyword(s):  
Complex Formation ◽  
Atpase Activity ◽  
Myosin Ii ◽  
Guanine Nucleotide Exchange Factors ◽  
Guanine Nucleotide ◽  
Nucleotide Exchange ◽  
Guanine Nucleotide Exchange ◽  
Nucleotide Exchange Factors ◽  
Cell Protrusion ◽  
Focal Complex

Cell migration requires the coordinated spatiotemporal regulation of actomyosin contraction and cell protrusion/adhesion. Nonmuscle myosin II (MII) controls Rac1 and Cdc42 activation, and cell protrusion and focal complex formation in migrating cells. However, these mechanisms are poorly understood. Here, we show that MII interacts specifically with multiple Dbl family guanine nucleotide exchange factors (GEFs). Binding is mediated by the conserved tandem Dbl homology–pleckstrin homology module, the catalytic site of these GEFs, with dissociation constants of ∼0.3 µM. Binding to the GEFs required assembly of the MII into filaments and actin-stimulated ATPase activity. Binding of MII suppressed GEF activity. Accordingly, inhibition of MII ATPase activity caused release of GEFs and activation of Rho GTPases. Depletion of βPIX GEF in migrating NIH3T3 fibroblasts suppressed lamellipodial protrusions and focal complex formation induced by MII inhibition. The results elucidate a functional link between MII and Rac1/Cdc42 GTPases, which may regulate protrusion/adhesion dynamics in migrating cells.

Abdominal Mucinous Cystic Neoplasm in a Male Child

2008 ◽  
Vol 11 (1) ◽  
pp. 46-49 ◽  
Author(s):  
Jean J. Luo ◽  
Fabien K. Baksh ◽  
John D. Pfeifer ◽  
James T. Eastman ◽  
Frederick C. Beyer ◽  
...  
Keyword(s):  
Soft Tissues ◽  
Abdominal Mass ◽  
Progesterone Receptors ◽  
Mucinous Cystadenoma ◽  
Mucinous Cystic Neoplasm ◽  
Cystic Neoplasm ◽  
Cystic Neoplasms ◽  
Pediatric Pathologist ◽  
Focal Complex ◽  
Hepatobiliary Tract

Mucinous cystic neoplasms (MCNs) make up a morphologic family of similar appearing tumors arising in the ovary and various extraovarian sites, including the pancreas, hepatobiliary tract, paratesticular soft tissues, and mesentery. Other than the uncommon mucinous cystadenoma of the ovary presenting in adolescence, MCNs are rarely seen by the pediatric pathologist. The present case is a 5-year-old boy with an abdominal mass appearing to arise in the mesentery of the small intestine. Because of its unresect-ability, a generous biopsy was performed and disclosed a MCN with focal complex papillary architecture in the absence of appreciable cytologic atypia or invasion into the wall. Like other MCNs, this tumor had an inhibin-positive, ovarian-like stroma that was nonreactive for estrogen and progesterone receptors. Only 1 other case of a mesenteric MCN has been reported to date in a child and none in a male. The MCN of the mesentery joins other, somewhat more common cystic lesions of the omentum and mesentery presenting in childhood.

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