No abstract

Cell polarity proteins regulate tight junction formation and directional migration in epithelial cells. To date, the mechanism by which these polarity proteins assemble at the leading edge of migrating epithelial cells remains unclear. We report that occludin, a transmembrane protein, is localized at the leading edge of migrating cells and regulates directional cell migration. During migration, occludin knockdown disrupted accumulation of aPKC-Par3 and PATJ at the leading edge, and led to a disorganized microtubule network and defective reorientation of the microtubule organization center (MTOC). Phosphorylation of occludin at tyrosine 473 residue allowed recruitment of p85 alpha to the leading edge via association with its C-terminal SH2 domain. Loss of occludin attenuated activation of PI3K, leading to disorganization of the actin cytoskeleton and reduced cell protrusions. Our data indicate that occludin is required for the leading-edge localization of polarity proteins aPKC-Par3 and PATJ and promotes cell protrusion by regulating membrane-localized activation of PI3K.

Soft actuators with accurate and real-time motion perception are of great importance for flexible machines and artificial intelligence robotics to enable an autonomic response to surroundings. To enhance the sensing-signal reliability and calibration, synchronous motion perception with multiplex feedback signals is desired but has not been sufficiently explored. Herein, we present a soft bimorph actuator that has electrical and visual dual channel signal feedback functions for real-time multiplex motion perception. Cellulose paper and polyimide tape were assembled together as bimorph actuation layers on which an MXene/graphene bilayer was coated for electrothermal function and electrical signal feedback and a thermochromic interlayer was used for real-time visual signal feedback. Based on the proposed actuators, three kinds of bionic robotics and an electro-puppetry robot, "Wu Song Fights the Tiger", with motion-programmable