BIOC 212 Lecture Notes - Lecture 9: Secretion, Membrane Transport, Cytosol
14 Oct 2015
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Document Summary
Post-translational import: translocation at the er is required to be co-translational. Import into nucleus and mitochondria is post-translational also not in secretory pathway. Interaction with cytosolic chaperones and/or targeting factors (importins, or exportins/ran for export) Receptors or transport complexes on the membrane (fg- nucleoporins) Mitochondria: double-membrane organelle each compartment has distinct functions and contents. Atp synthesis; metabolite transport: matrix: citric acid cycle, fatty acid and other metabolism. Intermembrane space (ims) and outer membrane(om): apoptosis control: om is permeable to small molecules through pores, but not folded proteins. Im is impermeable electrochemical h+ gradient is maintained. Membrane potential: respiration drives the transfer of protons from matrix to ims, the proton gradient drives generation of atp from adp, the electrochemical gradient, or membrane potential ( ) is important for other im functions. Mitochondrial targeting signals: matrix targeting signal (mts): 10-50 amino acids that form amphipathic helix hydrophobic on one side, positively charged on the other side.
