Bernhard Wehrle-Haller

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Trunk neural crest cells segregate from the neuroepithelium and enter a 'migration staging area' lateral to the embryonic neural tube. After some crest cells in the migration staging area have begun to migrate on a medial pathway, a subpopulation of crest-derived cells remaining in the migration staging area expresses mRNAs for the receptor tyrosine kinase,(More)
The actin cytoskeleton maintains the cellular architecture and mediates cell movements. To explore actin cytoskeletal dynamics, the enhanced green fluorescent protein (EGFP) was fused to human &bgr ;-actin. The fusion protein was incorporated into actin fibers which became depolymerized upon cytochalasin B treatment. This functional EGFP-actin construct(More)
During cell migration, the physical link between the extracellular substrate and the actin cytoskeleton mediated by receptors of the integrin family is constantly modified. We analyzed the mechanisms that regulate the clustering and incorporation of activated alphavbeta3 integrins into focal adhesions. Manganese (Mn2+) or mutational activation of integrins(More)
Integrins are cell-substrate adhesion molecules that provide the essential link between the actin cytoskeleton and the extracellular matrix during cell migration. We have analyzed alphaVbeta3-integrin dynamics in migrating cells using a green fluorescent protein-tagged beta3-integrin chain. At the cell front, adhesion sites containing alphaVbeta3-integrin(More)
Migrating cells are polarized with a protrusive lamella at the cell front followed by the main cell body and a retractable tail at the rear of the cell. The lamella terminates in ruffling lamellipodia that face the direction of migration. Although the role of actin in the formation of lamellipodia is well established, it remains unclear to what degree(More)
Cell adhesion, spreading and migration require the dynamic formation and dispersal of contacts with the extracellular matrix (ECM). In vivo, the number, availability and distribution of ECM binding sites dictate the shape of a cell and determine its mobility. To analyse the geometrical limits of ECM binding sites required for cell attachment and spreading,(More)
Integrin-dependent adhesion sites consist of clustered integrins that transmit mechanical forces and provide signaling required for cell survival and morphogenesis. Despite their importance, the regulation of integrin clustering by the cytoplasmic adapter protein talin (Tal) and phosphatidylinositol (PI)-4,5-biphosphate (PI(4,5)P(2)) lipids nor their(More)
Integrin-dependent cell adhesions come in different shapes and serve in different cell types for tasks ranging from cell-adhesion, migration, and the remodeling of the extracellular matrix to the formation and stabilization of immunological and chemical synapses. A major challenge consists in the identification of adhesion-specific as well as common(More)
The Patch (Ph) mutation in the mouse, a deletion that includes the gene for PDGFR alpha, is a recessive lethal that exhibits a dominant pigment phenotype in heterozygotes. To assess whether the Ph mutation acts cell-autonomously or non-autonomously on melanocyte development, we have examined the melanogenic potential of neural crest populations from normal(More)
The actin cytoskeleton of mature osteoclasts (OCs) adhering to nonmineralized substrates is organized in a belt of podosomes reminiscent of the sealing zone (SZ) found in bone resorbing OCs. In this study, we demonstrate that the belt is composed of two functionally different actin-based domains: podosome cores linked with CD44, which are involved in cell(More)