Nuclear Import/Export

Question 1

• Molecules imported? (4)
• Molecules Exported? (3)
• Both? (3)
• NPC (Nuclear pore complex): Static? Vary? Structure (3 parts) Nups (nucleoporins in which layers? Role of FG repeats? Increased NP residues leads to? NPC long lasting and at risk of what?
  1. ) How do small/neutral cross? Interaction with NPC?
  2. ) Facilitated Transport: Def? Diffusion? Max size? Interaction with NPC?

Answer 1

• RNA/DNA polymerase, protein kinase, histones
• ribosomal sub units, TRNA’s, mRNA’s
• BP, snRNA’s, TF’s
• No dilates/constricts; depending on cell; membrane layer, scaffold layer, barrier layer; SL, BL, non-cohesive domains; non cohesive parts, oxidative damage/leaky
• Diffusion; minimal
• cargo + receptor with energy coupled dissoc.; yes; 39nm; yes

Question 2

• Karyphorins: Def? Ex? (2) Family types? (2)
• Transport signals? (2) Rich in?
• Import complex?
• Export complex?
• Ran-GAP located where?
• a/B recycling? ATP needed?
• RanGTP high where? Ran ATP high where?
• NTF2?
• NLS/NES cleavage?

Answer 2

• Cargo transporters; Importins/Exportins; B receptor family = 1 kary + 1 cargo; a = 2 kary + 1 cargo
• NLS = in (K); NES = out (Leu)
• Ran GTP dissociates it once it enters nucleus
• Export Complex + NES + GTP from Ran
• on NPC to dissociate as it crosses
• yes; 2 gtp’s needed
• Nucleus; cytoplasm
• transports Ran GAP back to nucleus
• not cleaved so it can be reused

Question 3

• RNA export factors:
  1.) tRNA?
  2.) miRNA?
  3.) snRNA?
  4.) mRNA? unique how?
  5.) rRNA?
  Pathological Conditions related to:
• NPC?
• Transport Receptor? (2)
• Cargo? (4)

Answer 3

1. ) tRNA + Exp-T + Ran-GTP
2. ) miRNA + Exp-5 + Ran-GTP
3. ) snRNA + CRM1 + Ran-GTP
4. ) mRNA + NXt1 + nxf1 (ATP dependent helicase)
5. ) rRNA + NXT1 + NXF1 + CRM1 + Ran-GTP
   - some viruses create leaky valves
   - Oxidative stress model, neurodegenerative
   - NFAT, Swyer = SRY can’t bind NTR = xy female, AML = 2 NPC’s fuse or Nups fuse, Herpes caspids bypass NPC’s