Planar Polarity: Forcing Cells Into Line

Planar Polarity: Forcing Cells Into Line

Polarisation of tissues in the plane of an epithelium is fundamental for both animal morphogenesis and organ function. A new paper describes a role for mechanical cues in determining how such polarity is aligned with the body axes.

Forcing mycoplasma mobile into line.

Lateral Line: Precocious Phenotypes and Planar Polarity

Work on zebrafish mutants that develop supernumerary neuromasts in the lateral line has revealed an inhibitory mechanism, mediated by glial cells, that represses newly identified precursors of secondary neuromasts, ensuring successive waves of neuromast production occur on time. The alignment of hair cells in neuromasts corresponds to the timing of these waves.

Planar Polarity: Converting a Morphogen Gradient into Cellular Polarity

Epithelial cells are polarized within the apico-basal and planar axes. The latter - planar cell polarity - requires long-range regulation of orientation as well as short-range, cell-to-cell realignment through feedback loops. New insights into the long-range, gradient-type regulation reveal how a kinase translates the morphogen gradient input into cellular orientation.

The planar polarity pathway

to the brain and receive high-order commands and inputs from it. That is, much of the planning, computation and execution of stereotypic arm movements are conducted within the arm neural system itself. Accordingly, natural-looking arm extension movements can be generated in amputated arms. This organization may be an optimal solution for the motor control of highly redundant flexible appendages...