Figure 1.

Phosphorylation of Snx27 impairs cargo recognition. (A) Snx27, in association with retromer (the complex formed by Vps35, Vps29, and Vps26), sorts cargo proteins such as Glut-1 into tubules for recycling to the cell surface. (B) MAPK-mediated phosphorylation of the Snx27 PDZ domain impairs the affinity of Snx27 for binding some cargoes, thereby reducing endosome-to–cell surface recycling. Other machinery (e.g., retromer) is unaffected by Snx27 phosphorylation, and thus recycling can still occur, albeit less efficiently.