An EPHB4-RASA1 signaling complex inhibits shear stress-induced Ras-MAPK activation in lymphatic endothelial cells to promote the development of lymphatic vessel valves.

EPHB4 is a receptor protein tyrosine kinase that is required for the development of lymphatic vessel (LV) valves. We show here that EPHB4 is necessary for the specification of LV valves, their continued development after specification, and the maintenance of LV valves in adult mice. EPHB4 promotes LV valve development by inhibiting the activation of the Ras-MAPK pathway in LV endothelial cells (LEC).

Mechanical Conformers of Keyring Catenanes.

Interlocked molecules exhibit structural isomerization that is different from that of molecules whose connectedness is solely through covalent bonds. A mechanical bond, or the interlocking of components, provides a rich conformational landscape. The ability of synthetic chemists to design directional motion between these mechanical conformers suggests mechanical bonds as building blocks in the design of synthetic molecular motors and machines.

Rotaxane liquid crystals with variable length: The effect of switching efficiency on the isotropic-nematic transition.

We examine a solution of non-adaptive two-state rotaxane molecules which can switch from a short state of length L to a long state of length qL, using statistical thermodynamics. This molecular switching is externally driven and can result in an isotropic-nematic phase transition without altering temperature and concentration. Here we concentrate on the limitation imposed by switching inefficiency, i.

Triangular cyclic rotaxanes: Size, fluctuations, and switching properties.

We examine one of the simplest cyclic rotaxanes-a molecule made from three rods with variable length between 0 and L. This [3]rotaxane, unlike a traditional molecule, shows significant size and shape fluctuations. We quantify these using a number of different measures.