Biology 2382B Lecture 4: 4-Protein Synthesis
21 Apr 2016
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Learning objectives: protein-targeting, er: structure and function, contranslational translocation, protein modifications in er, mitochondrial import of proteins, chapter 13: p. 577-584, 594-599, 603-605. Protein sorting/targeting: typical mammalian cell has 10,000 proteins and must be localized correctly, newly made peptides must be directed to the correct destination, targeting is about directing proteins to the right destination (organelles) during. Or after synthesis: sorting is about directing proteins to the secretory pathway or non-secretory pathway. General principles of protein synthesis, targeting and sorting: many proteins are synthesized just by cytosolic ribosomes. Those are targeted to intracellular organelles such as er, mitochondria, chloroplasts, peroxisomes, and nucleus (they have a specific signal sequence: other proteins are synthesized by ribosomes attached to the rough er. These proteins reside in the er and proteins which are sorted to plasma membrane, golgi complex, and lysosomes: two major protein-sorting pathways: non-secretory and secretory. Basic mechanisms of protein targeting to the membranes of organelles are common:
