DHHC2 directly nucleates PSD-95 assembly at the plasma membrane through local palmitoylation. (A) HEK293T cells were cotransfected with a bi-cistronic RUSH vector containing streptavidin-Ii (Str-ER Hook) and streptavidin-binding peptide (SBP)-GFP-DHHC2 as well as PSD-95-mCherry. Synchronized release of DHHC2 from the ER was induced by the addition of biotin with or without 2-BP. Arrowheads denote signals at the plasma membrane. Bar, 10 µm. (B) Kymograph analysis. The fluorescence intensities of GFP and mCherry were measured along red lines in A. White arrows indicate the timing when DHHC2 arrived at the plasma membrane. Black arrows indicate the position of the plasma membrane (at 90 min). CS, inactive DHHC2. Bar, 2.5 µm.