PDI7 localization to the cis-Golgi and ER membranes
The classical protein disulfide isomerases (PDIs) reside in the endoplasmic reticulum and contain two thioredoxin catalytic domains and two redox-inactive-fold domains. In contrast, members of the PDI-C subfamily of plants lack the fold-domains, and contain a single thioredoxin domain flanked by conserved N- and C-terminal Pfam domains of the endoplasmic reticulum vesicle (type Erv41p/Erv46p)- cargo receptors. Yuen et al. (on pp. 993-1002) determined the subcellular localization of the PDI-C family member, PDI7. The cover image shows an electron tomography model of an Arabidopsis Golgi stack with the distribution of anti-PDI7 immunogold particles (yellow spheres) across the cis-Golgi cisternae (orange and green sacs). PDI7 localized almost exclusively at the cis-Golgi. PDI7 is proposed to function as a novel cargo receptor for proteins containing exposed cysteine residues.
Image supplied by Dr. Byung-Ho Kang (School of Life Sciences, CUHK), in collaboration with Dr. David Christopher (MBBE, University of Hawaii).