An understanding of chemotaxis at the level cell–molecule interactions is important because its relevance in cancer, immunology, and microbiology, just to name a few. This study quantifies effects flow on cell migration during microfluidic device. The gradient within device was modeled compared experimental results. Chemotaxis experiments were performed using chemokine CXCL8 under different rates with human HL60 promyelocytic leukemia cells expressing transfected CXCR2 receptor. Cell...

We have investigated the binding of soluble tenascin-C (TN-C) to several cell lines using a radioligand assay. Specific was demonstrated U-251MG human glioma cells and line bovine aortic endothelial cells, but hamster fibroblasts showed no specific binding. Recombinant proteins corresponding domains TN-C were used map site(s) in TN-C. The alternatively spliced segment (TNfnA-D) inhibited native most strongly, itself bound cells. Scatchard analysis TNfnA-D indicated 2-5 x 10(5) sites per...

In a previous study we demonstrated that the alternatively spliced region of tenascin-C, TNfnA-D, bound with high affinity to cell surface receptor, annexin II. present demonstrate three changes in cellular activity are produced by adding intact tenascin-C or TNfnA-D cells, and show all activities blocked antibodies against 1) added confluent endothelial cells induced loss focal adhesions. 2) mitogenic response confluent, growth-arrested 1% serum. stimulated mitogenesis only when it was...

Chemotaxis plays a central role in various biological processes, such as the movement of neutrophils and macrophage during wound healing aggregation Dictyostelium cells. During past few years, new understanding mechanisms controlling chemotaxis has been obtained through molecular genetic biochemical studies other experimental systems. This review outlines our present signaling pathways that allow cell to sense respond chemoattractant gradient. In response chemoattractants, cells either...

ABSTRACT We have found that endothelial cells adhere much more strongly than fibroblasts to domains of tenascin and fibronectin. Endothelial adhered weakly, without spreading, bacterial expression proteins corresponding the tenth fibronectin type III (FN-III) domain fibronectin, which contains RGD. A larger protein, containing this three amino-terminal ‘synergy’ gave strong adhesion spreading. Two widely separated adhesion. The third FN-III domain, TNfn3, an RGD sequence in human chicken...

We have identified a Dictyostelium discoideum gene encoding serine/threonine kinase, PAKa, putative member of the Ste20/PAK family p21-activated kinases, with kinase domain and long NH2-terminal regulatory containing an acidic segment, polyproline domain, CRIB domain. PAKa colocalizes myosin II to cleavage furrow dividing cells posterior polarized, chemotaxing via its paka null are defective in completing cytokinesis suspension. is also required for maintaining direction cell movement,...

We have used the chemotactic ability of Dictyostelium cells to examine roles Rho family members, known regulators assembly F-actin, in cell movement. Wild-type polarize with a leading edge enriched F-actin toward chemoattractant. Overexpression constitutively active Rac1B 61L or disruption DdRacGAP1, which encodes Rac1 GAP, induces membrane ruffles actin filaments around perimeter and increased levels resting cells. Whereas wild-type move linearly cAMP source, Ddracgap1 null make many wrong...

We have examined the function of a member vasodilator-stimulated phosphoprotein family proteins (DdVASP) in<i>Dictyostelium. Ddvasp</i> null cells lack filopodia, whereas targeting DdVASP to plasma membrane with myristoyl tag results in significant increase filopodia. The proline-rich domain-Ena/VASP homology 2 structure is required for both actin polymerization activity and filopodia formation.<i>Ddvasp</i> exhibit chemotaxis defect, which appears be due defect ability properly adhere...

ABSTRACT We have investigated the role of glycosaminoglycans in fibronectin matrix assembly and incorporation tenascin-C into fibrils. Chinese hamster ovary cell mutants with a total block heparan chondroitin sulfate production failed to assemble matrix, incorporated no tenascin-C. Another mutant reduced produced normal but incorporate Excess soluble inhibited binding purified ELISA, completely blocked Treating cultured cells xyloside, which interferes glycosaminoglycan attachment...

The small splice variant of tenascin-C (TN) has eight fibronectin type III (FN3) domains. major large three (in chicken) or seven human) additional FN3 domains inserted between five and six. Chiquet-Ehrismann et al. (Chiquet-Ehrismann, R., Matsuoka, Y., Hofer, U., Spring, J., Bernasconi, C., Chiquet, M. (1991, Cell Regul. 2, 927-938) demonstrated that the bound preferentially to in enzyme-linked immunosorbent assay, only was incorporated into matrix by cultures chicken fibroblasts. Here we...

Microglia, the immune competent cells of central nervous system (CNS), normally exist in a resting state characterized by ramified morphology with many processes, and become activated to amoeboid response brain injury, infection, variety neuroinflammatory stimuli. Many studies focused on how neurotransmitters affect microglia activation pathophysiological circumstances. In this study, we tried gain mechanistic insights dopamine (DA) released from neurons modulates cellular functions...

The actin cytoskeleton controls the overall structure of cells and is highly polarized in chemotaxing cells, with F-actin assembled predominantly anterior leading edge to a lesser degree cell's posterior. Wiskott-Aldrich syndrome protein (WASP) has emerged as central player controlling polymerization. We have investigated WASP function its regulation Dictyostelium demonstrated specific essential role organizing assembly cells. Cells expressing very low levels show reduced significant defects...

Evidence suggests that early life exposure to Bisphenol A (BPA) may impact neurobehavioral development in animals. BPA has been linked changes the dopamine level brain. However, molecular and cellular details of how causes these behavioral cognitive outcomes are poorly understood. We examined affects behaviors adult mice found induced hyperactivity abnormal reward feedback exposed at stage. hypothesized might cause by suppressing DAT trafficking. Fluorescence microscopy revealed YFP-DAT...

An assay for chemosensory responses by the ciliate Tetrahymena thermophila is described that uses glass capillaries with a rectangular cross-section (inner dimensions, 20 x 2 0.2 mm). These have optical and geometrical properties permitting convenient observation of cell behavior within capillaries. Washed cells, starved 12 h, accumulated preferentially in containing L-methionine, L-leucine, L-cysteine, L-histidine, L-histamine, cimetidine, agmatine, berenil at concentrations 10-3 M or less....

We have identified a developmentally regulated, putative MEK kinase (MEKKα) that contains an F-box and WD40 repeats plays complex role in regulating cell-type differentiation spatial patterning. Cells deficient MEKKα develop precociously exhibit abnormal patterning with increase one of the prestalk compartments (pstO), concomitant reduction prespore domain, loss sharp compartment boundaries, resulting overlapping domains. Overexpression or lacking results very delayed development severe...

WASP family proteins are key players for connecting multiple signaling pathways to F-actin polymerization. To dissect the highly integrated controlling activity, we identified a Rac protein that binds GTPase binding domain of WASP. Using two-hybrid and FRET-based functional assays, RacC as major regulator stimulates assembly in cell-free systems WASP-dependent manner. A microscopy approach showed local activation at leading edge chemotaxing cells. Cells overexpressing exhibit significant...

Abstract Microglia play crucial roles in increased inflammation the central nervous system upon brain injuries and diseases. Extracellular ADP has been reported to induce microglia chemotaxis membrane ruffle formation through P2Y 12 receptor. In this study, we examined role of ERK1/2 activation ADP‐induced chemotaxis. stimulation increases phosphorylation extracellular signal‐regulated kinase 1/2 (ERK1/2) paxillin at Tyr 31 Ser 83 . Inhibition significantly inhibited retraction ruffles,...