BIOL 102 Lecture Notes - Lecture 4: Signal Recognition Particle, Signal Peptidase, Covalent Bond
Document Summary
Er signal sequence is recognized by components of the cell. Srp binds to er signal sequence and pauses translation; srp binds to receptor in er membrane. The growing polypeptide is threaded into the channel. Er signal is cleaved by signal peptidase; protein is completely made and released into the er lumen. If there is no er retention, then vesicle transport occurs. After translation, proteins on golgi and er are covalently modified, groups are added through covalent bonds. Most proteins for mitochondria, chloroplasts, and all proteins for peroxisomes sorted post-translationally. Chaperones ex: holding protein in an unfolded state, job of others is to fold the protein in the correct manner. Proteasome/proteasome: part of the proteome (not to be confused) Role is to identify specific proteins that have been tagged in a certain way and to chop it up to prepared it for recycling. When the job of the protein has been done, they are targeted for destruction by the proteasome.
