Palmitoylation or, more specificaly S-acylation, plays important roles in theregulation of protein localization, stability, and activity. It is aposttranslational protein modification that involves the attachment ofpalmitic acid to Cys residues through a thioester linkage. Proteinacyltransferases (PATs), also known as palmitoyltransferases, catalyze thisreaction by transferring the palmitoyl group from palmitoyl-CoA to the thiolgroup of Cys residues. They are characterized by the presence of 50-residue-long domain called the DHHC domain, which in most but not all cases is alsocysteine-rich and gets its name from a highly conserved DHHC signaturetetrapeptide (Asp-His-His-Cys). The Cys residue within the DHHC domain forms astable acyl intermediate and transfers the acyl chain to the Cys residues of atarget protein [1,2].

Some of the proteins containing a DHHC domain are listed below:

• Drosophila DNZ1 protein.
• Mouse Abl-philin 2 (Aph2) protein. Interacts with c-Abl. May play a role in apoptosis.
• Mammalian ZDHHC9, an integral membrane protein.
• Yeast ankyrin repeat-containing protein AKR1.
• Yeast Erf2 protein. This protein localizes to the endoplasmic reticulum and seems to be important for Ras function [3].
• Arabidopsis thaliana tip growth defective 1 [4].

The profile we developed covers the entire DHHC domain.