Anchored by feedback

A pair of proteins, each individually incapable of maintaining a polar distribution, can convince each other to stay put at the ends of a fission yeast cell, according to Hilary Snaith and Ken Sawin (University of Edinburgh, Edinburgh, Scotland).

Polarity studies in fission yeast have focused on the tea1p protein. It can be seen hitching a ride on growing microtubules as they speed toward the two ends of the cell—the only sites where growth takes place in fission yeast. Now, Snaith and Sawin have found a protein called mod5p that is localized to cell ends and helps to keep the arriving tea1p anchored to those same sites. Cells lacking mod5p delivered tea1p as usual but failed to keep it localized at the cell ends. Mod5p, in turn, was...