gradient perceptionmedical dictionary

<cell biology> Problem faced by a cell that is to respond directionally to a gradient of, for example: a diffusible attractant chemical.

In a spatial mechanism the cell would compare receptor occupancy at different sites on the cell surface, a temporal mechanism would involve comparison of concentrations at different times, the cell moving randomly between readings.

In pseudospatial sensing, the cell would detect the gradient as a consequence of positive feedback to protrusive activity if receptor occupancy increased with time as the protrusion moved up gradient. Few cell types have been unambiguously shown to detect gradients.

This entry appears with permission from the Dictionary of Cell and Molecular Biology

(11 Mar 2008)