Mechanisms of Transport Across Membranes in Plant Chloroplasts

Plastids represent a family of organelles, which are ubiquitous in all plant cells. They have an outer and an inner envelope membrane, specialized in transport between the cytosol and the stroma. Green plastids (chloroplasts) have an additional internal membrane, named thylakoid membrane, specialized in photosynthetic light-dependent reactions. The envelope and thylakoid membrane of chloroplasts display a selective permeability since they allow substances of certain types and sizes to cross in certain amounts and at certain times. This contribution will review the current knowledge about mechanisms in transporting proteins, solutes and metabolites across envelope and thylakoid membranes in chloroplasts and about their importance for plant cell metabolism. Keywords: Chloroplast, envelope, metabolite transport, photosynthesis, protein transport, solute transport, endosymbiont hypothesis, Transporter Classification, thylakoid membrane, homodimerization