Clathrin adaptor proteins are essential for clathrin-coated vesicle biogenesis, yet the mechanisms governing their recruitment and interactions remain incompletely defined. The clathrin adaptors Gga and AP-1 are now shown to be recruited sequentially to the trans-Golgi network in two waves of clathrin coat assembly, coupled by Pik1-mediated phosphatidylinositol-4-phosphate synthesis. These findings reveal mechanistic insights into the functional and regulatory relationships between these clathrin adaptors.