proteinimport
Protein import refers to how cells move polypeptides from the cytosol into organelles and compartments. Most organellar proteins are synthesized as precursors on cytosolic ribosomes and must be delivered post-translationally or co-translationally. Successful import depends on targeting signals, chaperones, translocons, and energy sources.
Secretory and membrane proteins enter the endoplasmic reticulum co-translationally. A signal peptide emerges from the ribosome
Mitochondria and chloroplasts import use distinct outer and inner membrane complexes. Mitochondrial proteins use the TOM
Nuclear import delivers proteins through the nuclear pore complex using nuclear localization signals and transport receptors