MCB 150 Lecture Notes - Lecture 27: Signal Peptidase, Signal Peptide, Transmembrane Protein

• School: University of Illinois
• Department: Molecular and Cell Biology
• Course: MCB 150
• Professor: B Mehrtens

Document Summary

Single pass transmembrane protein: n-terminus in cytoplasm and c-terminus in lumenof er. Single pass transmembrane protein (2): c-terminus in cytoplasm and n-terminus in thelumen of the er. If you want protein to be in the membrane, you need to tell the translocon. Secondary signal called stop-transfer sequence gives instructions totranslocon to eject the protein out from between the two parts (squeeze theprotein) Once protein is ejected out of the translocon, ribosome continues translation until a stopcodon is reached, and then the rest of the protein is left in the cytoplasmtransmembrane proteins with. Signal peptide that is at the amino terminus- amino terminal signal peptide. Signal peptide other than the amino terminus- internal signal peptide. Don"t cut of internal signal sequence need it to be in a membrane spanningdomain, also would lose amino acids that could be important in the beginningof the protein. Acts as a signal peptide, but isn"t substrate for signal peptidase (can tell the difference)