Genomics and localization of the Arabidopsis DHHC-cysteine-rich domain S-acyltransferase protein family.

Protein lipid modification of cysteine residues, referred to as S-palmitoylation or S-acylation, is an important secondary and reversible modification that regulates membrane association, trafficking, and function of target proteins. This enzymatic reaction is mediated by protein S-acyl transferases (PATs). Here, the phylogeny, genomic organization, protein topology, expression, and localization pattern of the 24 PAT family members from Arabidopsis (Arabidopsis thaliana) is described. Most PATs are expressed at ubiquitous levels and tissues throughout the development, while few genes are expressed especially during flower development preferentially in pollen and stamen. The proteins display large sequence and structural variations but exhibit a common protein topology that is preserved in PATs from various organisms. Arabidopsis PAT proteins display a complex targeting pattern and were detected at the endoplasmic reticulum, Golgi, endosomal compartments, and the vacuolar membrane. However, most proteins were targeted to the plasma membrane. This large concentration of plant PAT activity to the plasma membrane suggests that the plant cellular S-acylation machinery is functionally different compared with that of yeast (Saccharomyces cerevisiae) and mammalians.