CronenbergerGwendolyn Quintana @011872351. Draw the nucleus and label all its parts. 2. Define (regarding protein transport through nuclear pores): a. Ran is a small protein initially located inside of the nucleus, which carries a molecule of GTP. Ran-GTP binds to a nuclear transport receptor and is transported through nuclear pores into the cytosol. After hydrolysis of GTP, Ran-GDP falls off the transport receptor and seeks out a protein destined for the nucleus. b. GTPase activating protein (GAP) regulates protein activity by phosphate addition and removal to GTP. Activation of GTP requires a tightly bound GTP to a GTP-binding protein. c. Guanine nucleotide exchange factor (GEF) activate GTPases by stimulating the release ofGDP to allow binding of GTP. d. Nuclear transport factor 2 (NTF2) is a protein that interacts with the nuclear pore complex glycoprotein and returns Ran-GDP back to the nucleoplasm. e. Importin is a protein that moves other protein molecules into the nucleus by binding to a specific recognition sequence, or nuclear localization signal. f. Exportin a molecule which bind signaling sequences called nuclear export signals (NES) to facilitate exit from the nucleus. They must bind RanGTP to form a ternary complex with their export cargo. 3. Trace the Ran cycle into/out of the nucleus. Include influences of Ran on importine/exportin: cargoa. Promotion of complex formation: Importin is a transport proteins that binds to nuclear localization signal of cargo protein in the cytoplasm. Hydrolysis allows for the dissociation of Ran-GTP and association of importin to the nuclear transport receptor. b. Dissociation of complex: The nuclear transport receptor becomes dissociated with the importin upon arrival into the nucleus by binds of GTP-Ran. This complex subsequently travels to the cytosol and become dissociated via hydrolysis and presence of nucleus-bound proteins.CronenbergerGwendolyn Quintana @011872354. Trace the protein import from the ribosomes into the nucleus. Include all
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