Biology Reference
In-Depth Information
FIGURE 9.4
Gradient sharpening by using a lower diffusion constant for the internal representation of the
gradient. This diagram considers only a single dimension along the axis of the cell: the reason that there are not
competing gradients coming from the sides of the cell is considered in the main text.
locates to the membrane but does so around the circumference of the cell.
11
It has not yet been
possible to image the location of PI(3,4,5)P
3
directly, but GFP-tagged proteins with PH
domains are targeted to the leading edge of the cell where PI-3-kinase is located, strongly
suggesting that this is where PI(3,4,5) is mainly found.
13
It has been suggested on theoretical
FIGURE 9.5
The gradient-sharpening effect of transducing an external signal to an internal one carried by
a molecule with a lower coefficient of diffusion, D.
