dictyNews
Electronic Edition
Volume 32, number 6
March 6, 2009

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Abstracts
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Review: Eukaryotic Chemotaxis

Wouter-Jan Rappel and William F. Loomis
Departments of Physics and Biology, University of California, San Diego


Wiley Interdisciplinary Reviews: Systems Biology and Medicine, in press

During eukaryotic chemotaxis, external chemical gradients guide the  
crawling
motion of cells. This process plays an important role in a large  
variety of
biological systems and has wide ranging medical implications. New
experimental techniques including confocal microscopy and microfluidics
have advanced our understanding of chemotaxis while numerical modeling
efforts are beginning to offer critical insights. In this short  
review, we
survey the current experimental status of the field by dividing  
chemotaxis
into three distinct 'modules': directional sensing, polarity and  
motility.
For each module, we attempt to point out potential new directions of  
research
and discuss how modeling studies interact with experimental  
investigations.


Submitted by: Bill Loomis [[log in to unmask]]
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Filopodia: Complex models for simple rods


Jan Faix (1), Dennis Breitsprecher (1), Theresia E.B. Stradal (2) and
Klemens Rottner (2).

(1) Inst. for Biophysical Chemistry, Hannover Medical School, Germany.
(2) Helmholz Center for Infection Research, Braunschweig, Germany.


International Journal of Biochemistry & Cell Biology, in press.

Filopodia are prominent cell surface projections filled with bundles  
of linear
actin filaments that drive their protrusion. These structures are  
considered
important sensory organelles, for instance in neuronal growth cones or  
during
the fusion of sheets of epithelial tissues. In addition, they can  
serve a
precursor function in adhesion site or stress fibre formation. Actin  
filament
assembly is essential for filopodia formation and turnover, yet the  
precise
molecular mechanisms of filament nucleation and/or elongation are
controversial. Indeed, conflicting reports on the molecular  
requirements of
filopodia initiation have prompted researchers to propose different  
types
and/or alternative or redundant mechanisms mediating this process.
However, recent data shed new light on these questions, and they  
indicate
that the balance of a limited set of biochemical activities can  
determine the
structural outcome of a given filopodium. Here we focus on discussing  
our
current view of the relevance of these activities, and attempt to  
propose a
molecular mechanism of filopodia assembly based on a single core
machinery.


Submitted by: Hans Faix [[log in to unmask]]
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[End dictyNews, volume 32, number 6]