FOCAL POINT  Two groups find that the enzyme Sac2 is a PI 4-phosphatase that localizes to early endosomes and hydrolyzes PI(4)P. (Top row) FoSheng Hsu (left), Yuxin Mao (right), and Fenghua Hu (not pictured) reveal that, compared with control cells (middle row, left), PI(4)P (green) accumulates on endosomes (red) in the absence of Sac2 (center), which inhibits endocytic recycling and slows cell migration. (Bottom row) Fubito Nakatsu (left), Pietro De Camilli (right), and colleagues (not pictured) demonstrate that the small GTPase Rab5 promotes the formation of a complex between (middle row, right) Sac2 (green) and the PI 5-phosphatase OCRL (red) that might serve to sequentially dephosphorylate endosomal PI(4,5)P₂ in a similar manner to the synaptojanin family of dual PI phosphatases.

PHOTOS COURTESY OF THE AUTHORS