Cell biology: watching the first steps of podosome formation.

Podosomes and invadopodia are actin-rich structures that have come under intense scrutiny over the past several years due to their critical roles in cell migration and invasion. Examination of the initial stages of podosome formation has revealed an important role for the phosphoinositide PI(3,4)P(2) in anchoring the scaffold protein Tks5 to the plasma membrane.