3 research outputs found
Role of Drosophila Rab5 during endosomal trafficking at the synapse and evoked neurotransmitter release
Neuronale Stamm- und Vorlaeuferzellen
Das zentrale Nervensystem von Wirbeltieren entsteht in der Embryonalentwicklung aus einem einschichtigen Epithel, dem Neuroepithel. Waehrend der Neurogenese bildet sich aus diesem einfachen Epithel das komplexe Netzwerk des vielschichtigen Gehirngewebes. Dabei produzieren neurale Stammzellen und die aus ihnen hervorgehenden neuronalen Vorlaeuferzellen (die wir der Einfachheit halber beide unter dem Oberbegriff progenitors zusammenfassen) alle Nervenzellen (Neurone) des Gehirns
Bile canaliculi remodeling activates YAP via the actin cytoskeleton during liver regeneration
Abstract The mechanisms of organ size control remain poorly understood. A key question is how cells collectively sense the overall status of a tissue. We addressed this problem focusing on mouse liver regeneration. Using digital tissue reconstruction and quantitative image analysis, we found that the apical surface of hepatocytes forming the bile canalicular network expands concomitant with an increase in Fâactin and phosphoâmyosin, to compensate an overload of bile acids. These changes are sensed by the Hippo transcriptional coâactivator YAP, which localizes to apical Fâactinârich regions and translocates to the nucleus in dependence of the integrity of the actin cytoskeleton. This mechanism tolerates moderate bile acid fluctuations under tissue homeostasis, but activates YAP in response to sustained bile acid overload. Using an integrated biophysicalâbiochemical model of bile pressure and Hippo signaling, we explained this behavior by the existence of a mechanoâsensory mechanism that activates YAP in a switchâlike manner. We propose that the apical surface of hepatocytes acts as a selfâregulatory mechanoâsensory system that responds to critical levels of bile acids as readout of tissue status