Minimal membrane targeting domain of SNAP25b. A, SNAP25b contains a minimal membrane targeting sequence that is located between amino acids 85 and 120. Palmitoylated cysteines in this domain are shown in bold and underlined. The QPARV motif, which is underlined with a dashed line is important for DHHC interactions of SNAP25b. B, comparison is shown of the cysteine-rich domains of SNAP25a, SNAP25b, and SNAP23. The QPARV motif in SNAP25b is conserved in SNAP25a, whereas mouse SNAP23 contains the sequence QPSRI. Amino acid numbers are shown.