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Dive into the research topics where Anna Huttenlocher is active.

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Featured researches published by Anna Huttenlocher.


Current Opinion in Cell Biology | 1995

ADHESION IN CELL MIGRATION

Anna Huttenlocher; Rebecca R Sandborg; Alan F. Horwitz

Adhesive interactions play a central role in cell migration. The regulation of these interactions requires the coordination of a multiplicity of signals, both spatially and temporally. The role of the integrin family has received considerable recent attention. Progress has been made in the elucidation of the mechanisms by which growth factors and other motogenic factors stimulate migration. Major advances have also been made in understanding the mechanisms by which the formation and breakdown of adhesive complexes are regulated, including the participation of members of the rho family. Despite these advances, many important questions remain, and the field seems well positioned to answer them.


Nature Cell Biology | 2004

Calpain-mediated proteolysis of talin regulates adhesion dynamics

Santos J. Franco; Mary A. Rodgers; Benjamin J. Perrin; Jaewon Han; David A. Bennin; David R. Critchley; Anna Huttenlocher

Dynamic regulation of adhesion complexes is required for cell migration and has therefore emerged as a key issue in the study of cell motility. Recent progress has been made in defining some of the molecular mechanisms by which adhesion disassembly is regulated, including the contributions of adhesion adaptor proteins and tyrosine kinases. However, little is known about the potential contribution of proteolytic mechanisms to the regulation of adhesion complex dynamics. Here, we show that proteolysis of talin by the intracellular calcium-dependent protease calpain is critical for focal adhesion disassembly. We have generated a single point mutation in talin that renders it resistant to proteolysis by calpain. Quantification of adhesion assembly and disassembly rates demonstrates that calpain-mediated talin proteolysis is a rate-limiting step during adhesion turnover. Furthermore, we demonstrate that disassembly of other adhesion components, including paxillin, vinculin and zyxin, is also dependent on the ability of calpain to cleave talin, suggesting a general role for talin proteolysis in regulating adhesion turnover. Together, these findings identify calpain-mediated proteolysis of talin as a mechanism by which adhesion dynamics are regulated.


Cold Spring Harbor Perspectives in Biology | 2011

Integrins in Cell Migration

Anna Huttenlocher; Alan Rick Horwitz

Integrin-based adhesion has served as a model for studying the central role of adhesion in migration. In this article, we outline modes of migration, both integrin-dependent and -independent in vitro and in vivo. We next discuss the roles of adhesion contacts as signaling centers and linkages between the ECM and actin that allows adhesions to serve as traction sites. This includes signaling complexes that regulate migration and the interplay among adhesion, signaling, and pliability of the substratum. Finally, we address mechanisms of adhesion assembly and disassembly and the role of adhesion in cellular polarity.


Journal of Cell Science | 2005

Regulating cell migration: calpains make the cut

Santos J. Franco; Anna Huttenlocher

The calpain family of proteases has been implicated in cellular processes such as apoptosis, proliferation and cell migration. Calpains are involved in several key aspects of migration, including: adhesion and spreading; detachment of the rear; integrin- and growth-factor-mediated signaling; and membrane protrusion. Our understanding of how calpains are activated and regulated during cell migration has increased as studies have identified roles for calcium and phospholipid binding, autolysis, phosphorylation and inhibition by calpastatin in the modulation of calpain activity. Knockout and knockdown approaches have also contributed significantly to our knowledge of calpain biology, particularly with respect to the specific functions of different calpain isoforms. The mechanisms by which calpain-mediated proteolysis of individual substrates contributes to cell motility have begun to be addressed, and these efforts have revealed roles for proteolysis of specific substrates in integrin activation, adhesion complex turnover and membrane protrusion dynamics. Understanding these mechanisms should provide avenues for novel therapeutic strategies to treat pathological processes such as tumor metastasis and chronic inflammatory disease.


Journal of Biological Chemistry | 1997

Regulation of Cell Migration by the Calcium-dependent Protease Calpain

Anna Huttenlocher; Sean P. Palecek; Qin Lu; Wenli Zhang; Ronald L. Mellgren; Douglas A. Lauffenburger; Mark H. Ginsberg; Alan F. Horwitz

Integrin receptors play an important role during cell migration by mediating linkages and transmitting forces between the extracellular matrix and the actin cytoskeleton. The mechanisms by which these linkages are regulated and released during migration are not well understood. We show here that cell-permeable inhibitors of the calcium-dependent protease calpain inhibit both β1 and β3 integrin-mediated cell migration. Calpain inhibition specifically stabilizes peripheral focal adhesions, increases adhesiveness, and decreases the rate of cell detachment. Furthermore, these inhibitors alter the fate of integrin receptors at the rear of the cell during migration. A Chinese hamster ovary cell line expressing low levels of calpain I also shows reduced migration rates with similar morphological changes, further implicating calpain in this process. Taken together, the data suggest that calpain inhibition modulates cell migration by stabilizing cytoskeletal linkages and decreasing the rate of retraction of the cell’s rear. Inhibiting calpain-mediated proteolysis may therefore be a potential therapeutic approach to control pathological cell migration such as tumor metastasis.


Journal of Leukocyte Biology | 2006

Resolution of inflammation by retrograde chemotaxis of neutrophils in transgenic zebrafish

Jonathan R. Mathias; Benjamin J. Perrin; Ting Xi Liu; John P. Kanki; A. Thomas Look; Anna Huttenlocher

Neutrophil chemotaxis to sites of inflammation is a critical process during normal immune responses to tissue injury and infection and pathological immune responses leading to chronic inflammation. Although progress has been made in understanding the mechanisms that promote neutrophil recruitment to inflamed tissue, the mechanisms that regulate the resolution phase of the inflammatory response have remained relatively elusive. To define the mechanisms that regulate neutrophil‐mediated inflammation in vivo, we have developed a novel transgenic zebrafish in which the neutrophils express GFP under control of the myeloperoxidase promoter (zMPO:GFP). Tissue injury induces a robust, inflammatory response, which is characterized by the rapid chemotaxis of neutrophils to the wound site. In vivo time‐lapse imaging shows that neutrophils subsequently display directed retrograde chemotaxis back toward the vasculature. These findings implicate retrograde chemotaxis as a novel mechanism that regulates the resolution phase of the inflammatory response. The zMPO:GFP zebrafish provides unique insight into the mechanisms of neutrophil‐mediated inflammation and thereby offers opportunities to identify new regulators of the inflammatory response in vivo.


Nature | 2011

Lyn is a redox sensor that mediates leukocyte wound attraction in vivo

Sa Kan Yoo; Taylor W. Starnes; Qing Deng; Anna Huttenlocher

Tissue wounding induces the rapid recruitment of leukocytes. Wounds and tumours—a type of ‘unhealed wound’—generate hydrogen peroxide (H2O2) through an NADPH oxidase (NOX). This extracellular H2O2 mediates recruitment of leukocytes, particularly the first responders of innate immunity, neutrophils, to injured tissue. However, the sensor that neutrophils use to detect the redox state at wounds is unknown. Here we identify the Src family kinase (SFK) Lyn as a redox sensor that mediates initial neutrophil recruitment to wounds in zebrafish larvae. Lyn activation in neutrophils is dependent on wound-derived H2O2 after tissue injury, and inhibition of Lyn attenuates neutrophil wound recruitment. Inhibition of SFKs also disrupted H2O2-mediated chemotaxis of primary human neutrophils. In vitro analysis identified a single cysteine residue, C466, as being responsible for direct oxidation-mediated activation of Lyn. Furthermore, transgenic-tissue-specific reconstitution with wild-type Lyn and a cysteine mutant revealed that Lyn C466 is important for the neutrophil wound response and downstream signalling in vivo. This is the first identification, to our knowledge, of a physiological redox sensor that mediates leukocyte wound attraction in multicellular organisms.


Journal of Biological Chemistry | 2001

Reduced Cell Migration and Disruption of the Actin Cytoskeleton in Calpain-deficient Embryonic Fibroblasts

Nathalie Dourdin; Amit Bhatt; Previn Dutt; Peter A. Greer; J. Simon; C. Arthur; John S. Elce; Anna Huttenlocher

The physiological functions and substrates of the calcium-dependent protease calpain remain only partly understood. The μ- and m-calpains consist of a μ- or m-80-kDa large subunit (genes Capn1 and Capn2), and a common 28-kDa small subunit (Capn4). To assess the role of calpain in migration, we used fibroblasts obtained fromCapn4−/− mouse embryos. The cells lacked calpain activity on casein zymography and did not generate the characteristic calpain-generated spectrin breakdown product that is observed in wild-type cells. Capn4−/− cells had decreased migration rates and abnormal organization of the actin cytoskeleton with a loss of central stress fibers. Interestingly, these cells extended numerous thin projections and displayed delayed retraction of membrane protrusions and filopodia. The number of focal adhesions was decreased in Capn4−/− cells, but the cells had prominent vinculin-containing focal complexes at the cell periphery. The levels of the focal adhesion proteins, α-actinin, focal adhesion kinase (FAK), spectrin, talin, and vinculin, were the same in Capn4+/+ andCapn4−/− cells. FAK, α-actinin, and vinculin were not cleaved in either cell type plated on fibronectin. However, proteolysis of the focal complex component, talin, was detected in the wild-type cells but not in theCapn4−/− cells, suggesting that calpain cleavage of talin is important during cell migration. Moreover, talin cleavage was again observed when calpain activity was partially restored in Capn4−/− embryonic fibroblasts by stable transfection with a vector expressing the rat 28-kDa calpain small subunit. The results demonstrate unequivocally that calpain is a critical regulator of cell migration and of the organization of the actin cytoskeleton and focal adhesions.


Developmental Cell | 2010

Differential Regulation of Protrusion and Polarity by PI(3)K during Neutrophil Motility in Live Zebrafish

Sa Kan Yoo; Qing Deng; Peter J. Cavnar; Yi I. Wu; Klaus M. Hahn; Anna Huttenlocher

Cell polarity is crucial for directed migration. Here we show that phosphoinositide 3-kinase (PI(3)K) mediates neutrophil migration in vivo by differentially regulating cell protrusion and polarity. The dynamics of PI(3)K products PI(3,4,5)P(3)-PI(3,4)P(2) during neutrophil migration were visualized in living zebrafish, revealing that PI(3)K activation at the leading edge is critical for neutrophil motility in intact tissues. A genetically encoded photoactivatable Rac was used to demonstrate that localized activation of Rac is sufficient to direct migration with precise temporal and spatial control in vivo. Similar stimulation of PI(3)K-inhibited cells did not direct migration. Localized Rac activation rescued membrane protrusion but not anteroposterior polarization of F-actin dynamics of PI(3)K-inhibited cells. Uncoupling Rac-mediated protrusion and polarization suggests a paradigm of two-tiered PI(3)K-mediated regulation of cell motility. This work provides new insight into how cell signaling at the front and back of the cell is coordinated during polarized cell migration in intact tissues within a multicellular organism.


Nature Cell Biology | 2001

Increased filamin binding to β-integrin cytoplasmic domains inhibits cell migration

David A. Calderwood; Anna Huttenlocher; William B. Kiosses; David M. Rose; Darren G. Woodside; Martin A. Schwartz; Mark H. Ginsberg

Multicellular animal development depends on integrins. These adhesion receptors link to the actin cytoskeleton, transmitting biochemical signals and force during cell migration and interactions with the extracellular matrix. Many integrin–cytoskeleton connections are formed by filamins and talin. The β7 integrin tail binds strongly to filamin and supports less migration, fibronectin matrix assembly and focal adhesion formation than either the β1D tail, which binds strongly to talin, or the β1A tail, which binds modestly to both filamin and talin. To probe the role of filamin binding, we mapped the filamin-binding site of integrin tails and identified amino acid substitutions that led to selective loss of filamin binding to the β7 tail and gain of filamin binding to the β1A tail. These changes affected cell migration and membrane protrusions but not fibronectin matrix assembly or focal adhesion formation. Thus, tight filamin binding restricts integrin-dependent cell migration by inhibiting transient membrane protrusion and cell polarization.

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David J. Beebe

University of Wisconsin-Madison

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David A. Bennin

University of Wisconsin-Madison

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Mary A. Lokuta

University of Wisconsin-Madison

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Sarah A. Wernimont

University of Wisconsin-Madison

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Sa Kan Yoo

University of Wisconsin-Madison

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Christa L. Cortesio

University of Wisconsin-Madison

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Erwin Berthier

University of Wisconsin-Madison

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Nancy P. Keller

University of Wisconsin-Madison

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