Thylakoid Protein Targeting Pathways

Thylakoid protein targeting pathways move precursor proteins to the chloroplast thylakoids, where photosynthesis takes place. Thylakoids are membrane-bound sac-like structures inside the chloroplast. Their lumen holds many electron transport proteins, and their membrane is rich in the light-harvesting complex.

Proteins directed to the thylakoids carry sub-organellar targeting signals in addition to the transit signal. Thylakoid protein sorting occurs by distinct pathways: the chloroplast secretory or cpSec pathway, the chloroplast twin-arginine or cpTat pathway, and the chloroplast signal recognition particle, or cpSRP pathway.

The cpSec pathwa...