BIOLOGY 2B03 Lecture Notes - Lecture 3: Autocrine Signalling, Copi, Dissociation Constant
17 Dec 2015
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Peroxisomal proteins are synthesized in the cytosol and then transported to a peroxisome. A: peroxisomal- targeting sequence = pts1: ser- lys- leu (skl) at c- terminus. B: pex5 binds pts1 in cytosol. B: pex5 associates with pex14 in peroxisomal membrane protein. C: protein/pex5 is transferred to translocon (pex10, 2, 12) and move through the channel: translocation requires atp hydrolysis. C: pex5 dissociates from the protein within the peroxisomal matrix and is recycled back into the cytosol. Mitochondrial proteins are synthesized and translated outside of the mitochondria and then transported into mitochondria. Mitochondrial proteins are imported as unfolded peptide chains: chaperone hsc70 keeps the polypeptide unfolded. C: hsc70 cleaves mts. 2: protein is transferred laterally into the membrane. N- terminal targeting motif: rich in ser, thr, ala, val. C- terminal nuclear localization sequence (nls) Lumen targeting: 1: er signal sequence (ess) on the protein being synthesized directs ribosome to er membrane.
