Figure 4.

Protein topology of Arabidopsis PATs. A, Overview of the protein topology of Arabidopsis PAT proteins. Given are the relative positions of the potential TMDs and the variable N- and C-terminal regions. The central region contains the DHHC sequence (gray triangle) in the vicinity of the C-terminal TMDs. Black boxes represent predicted TMDs (with support values in percent, given from 0–1). Light-gray boxes represent further hydrophobic domains, which likely do not represent TMDs (support value <0.5). The identified ankyrin domains are shown for the AtPATs 23 and 24 in the N-terminal region. The box within the C-terminal region of AtPAT4 represents a His-rich region. Bar represents 100 amino acids. B, Proposed protein topology of Arabidopsis PATs within the membrane. Most PATs contain two TMDs upstream of the central region (AtPATx). In general, the N terminus, the central DHHC-CRD (DHHC), and the C terminus are directed to the cytosol. AtPAT15 likely contains only one predicted TMD, which is preceding the DHHC-CRD. To direct the active site to the cytosol, the N terminus has to be secreted. [See online article for color version of this figure.]