Faculty Opinions recommendation of Lamellipodial actin mechanically links myosin activity with adhesion-site formation.

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.

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Memo–RhoA–mDia1 signaling controls microtubules, the actin network, and adhesion site formation in migrating cells

The Journal of Cell Biology ◽

10.1083/jcb.200805107 ◽

2008 ◽

Vol 183 (3) ◽

pp. 401-408 ◽

Cited By ~ 78

Author(s):

Kossay Zaoui ◽

Stéphane Honoré ◽

Daniel Isnardon ◽

Diane Braguer ◽

Ali Badache

Keyword(s):

Cell Migration ◽

Leading Edge ◽

Site Formation ◽

Actin Assembly ◽

Actin Network ◽

Adhesion Sites ◽

Cell Front ◽

Guanosine Triphosphatase ◽

Adhesion Site ◽

Migrating Cells

Actin assembly at the cell front drives membrane protrusion and initiates the cell migration cycle. Microtubules (MTs) extend within forward protrusions to sustain cell polarity and promote adhesion site turnover. Memo is an effector of the ErbB2 receptor tyrosine kinase involved in breast carcinoma cell migration. However, its mechanism of action remained unknown. We report in this study that Memo controls ErbB2-regulated MT dynamics by altering the transition frequency between MT growth and shortening phases. Moreover, although Memo-depleted cells can assemble the Rac1-dependent actin meshwork and form lamellipodia, they show defective localization of lamellipodial markers such as α-actinin-1 and a reduced number of short-lived adhesion sites underlying the advancing edge of migrating cells. Finally, we demonstrate that Memo is required for the localization of the RhoA guanosine triphosphatase and its effector mDia1 to the plasma membrane and that Memo–RhoA–mDia1 signaling coordinates the organization of the lamellipodial actin network, adhesion site formation, and MT outgrowth within the cell leading edge to sustain cell motility.

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Talin1 is critical for force-dependent reinforcement of initial integrin–cytoskeleton bonds but not tyrosine kinase activation

The Journal of Cell Biology ◽

10.1083/jcb.200302001 ◽

2003 ◽

Vol 163 (2) ◽

pp. 409-419 ◽

Cited By ~ 179

Author(s):

Grégory Giannone ◽

Guoying Jiang ◽

Deborah H. Sutton ◽

David R. Critchley ◽

Michael P. Sheetz

Keyword(s):

Tyrosine Kinase ◽

Tyrosine Kinases ◽

Structural Changes ◽

Cytoskeletal Proteins ◽

Site Formation ◽

Laser Tweezers ◽

Kinase Activation ◽

Adhesion Sites ◽

The Relationship ◽

Adhesion Site

Cells rapidly transduce forces exerted on extracellular matrix contacts into tyrosine kinase activation and recruitment of cytoskeletal proteins to reinforce integrin–cytoskeleton connections and initiate adhesion site formation. The relationship between these two processes has not been defined, particularly at the submicrometer level. Using talin1-deficient cells, it appears that talin1 is critical for building early mechanical linkages. Deletion of talin1 blocked laser tweezers, force-dependent reinforcement of submicrometer fibronectin-coated beads and early formation of adhesion sites in response to force, even though Src family kinases, focal adhesion kinase, and spreading were activated normally. Recruitment of vinculin and paxillin to sites of force application also required talin1. FilaminA had a secondary role in strengthening fibronectin–integrin–cytoskeleton connections and no role in stretch-dependent adhesion site assembly. Thus, force-dependent activation of tyrosine kinases is independent of early force-dependent structural changes that require talin1 as part of a critical scaffold.

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Presenilin 1 Affects Focal Adhesion Site Formation and Cell Force Generation via c-Src Transcriptional and Posttranslational Regulation

Journal of Biological Chemistry ◽

10.1074/jbc.m806825200 ◽

2009 ◽

Vol 284 (15) ◽

pp. 10138-10149 ◽

Cited By ~ 13

Author(s):

Dieter Waschbüsch ◽

Simone Born ◽

Verena Niediek ◽

Norbert Kirchgessner ◽

Irfan Y. Tamboli ◽

...

Keyword(s):

Focal Adhesion ◽

Force Generation ◽

Presenilin 1 ◽

Site Formation ◽

Posttranslational Regulation ◽

Cell Force ◽

Focal Adhesion Site ◽

Adhesion Site

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The repeat region of the circumsporozoite protein is an elastic linear spring with a functional role in Plasmodium sporozoite motility

10.1101/2021.05.12.443759 ◽

2021 ◽

Author(s):

Amanda Balaban ◽

Sachie Kanatani ◽

Jaba Mitra ◽

Jason Gregory ◽

Natasha Vartak ◽

...

Keyword(s):

Single Molecule ◽

Functional Role ◽

Malaria Vaccine ◽

Circumsporozoite Protein ◽

Site Formation ◽

Repeat Region ◽

Biophysical Properties ◽

Adhesion Sites ◽

Linear Spring ◽

Adhesion Site

The circumsporozoite protein (CSP) forms a dense coat on the surface of the sporozoite, the infective stage of the malaria parasite. The central repeat region of CSP is a critical component of the only licensed malaria vaccine yet little is known about its structure or function. We found that sporozoite mutants with severely truncated or scrambled repeats have impaired motility due to altered adhesion site formation and dynamics, suggesting that the CSP repeats provide a cohesive environment in which adhesion sites can form. We hypothesized that biophysical properties of the repeats are important in this role and interrogated this using single-molecule fluorescence-force spectroscopy. We show that the repeats are a stiff, linear spring with elastic properties, dependent upon length and lost when the repeats are scrambled. These data are the first evidence that the CSP repeat region serves a functional role during infection and motility, likely mediated through its biophysical properties.

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A Prehistoric Ford near Rough Castle, Falkirk

Scottish Archaeological Journal ◽

10.3366/saj.2001.23.2.91 ◽

2001 ◽

Vol 23 (2) ◽

pp. 91-103

Author(s):

JAMIE HAMILTON ◽

CIARA CLARKE ◽

ANDREW DUNWELL ◽

RICHARD TIPPING

Keyword(s):

Coal Mining ◽

Pollen Analysis ◽

Site Formation ◽

Site Formation Processes ◽

Formation Processes ◽

Radiocarbon Dates ◽

Small Stream ◽

Mining Project ◽

First Millennium

This report presents the results of the excavation of a stone ford laid across the base of a small stream valley near Rough Castle, Falkirk. It was discovered during an opencast coal mining project. Radiocarbon dates and pollen analysis of deposits overlying the ford combine to indicate a date for its construction no later than the early first millennium cal BC. Interpreting this evidence was not straightforward and the report raises significant issues about site formation processes and the interpretation of radiocarbon and pollen evidence. The importance of these issues extends beyond the rarely investigated features such as fords and deserve a larger place in the archaeological literature.

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