BIOL 2021 Chapter Notes - Chapter 12.6: Nuclear Export Signal, Nfat, Nuclear Pore

• School: York University
• Department: Biology
• Course: BIOL 2021
• Professor: Patricia Lakin- Thomas

Document Summary

Ran gtpase: required for nuclear import and export: exists in 2 conformational states and depends on whether gtp or gdp is bound (ran gtp or ram gdp, provides energy and directionality for import and export. Ran gap: gtpase-activating protein (ran gtp ran gdp: triggers gtp hydrolysis in the cytosol, exchanges gdp for a gtp. Ran gef: guanine exchange factor (ran gdp ran gtp: exchanges gdp for gtp in the nucleus, binds to chromatin fibres in the nucleus. Ran gdp + gtp ran gtp + gdp. Cytosol contains more ran gdp whereas nucleus contains more ran gtp. Nuclear import: receptor and cargo go in: ran gtp binds and releases the cargo, receptor and ran gtp go out, ran gap converts ran gtp to ran gdp in the cytosol and it dissociates from the receptor. Snrna, mirna, trna all use the same ran-gtp signal to get out of the nucleus: mrna-nucleoprotein complex uses a different mechanism to get out of the pore.