Nuclear Targeting

Question 1

What is step 1?

Answer 1

protein contains Nuclear Localisation Sequence (4-8 basic amino acids in primary sequence, arg/lys)

Question 2

What is step 2?

Answer 2

protein binds to a carrier protein called importin in cytosol

Question 3

What is step 3?

Answer 3

fully folded protein translocated into nucleus via nuclear pore (energy dependant)

Question 4

What is step 4?

Answer 4

protein released, importin binds to ranGTP (small GTPase), this causes a conformational change

Question 5

What is step 5?

Answer 5

importin exported from nucleus & recycled

Question 6

What is step 6?

Answer 6

Ran transported back to nucleus following GTP hydrolysis

Question 7

What is Swyer Syndrome?

Answer 7

Loss or mutation of NLS in sex determining region Y (SRY) protein
• XY genotype, outwardly female
• SRY required for testis differentiation

Question 8

What is Leri-Weill dyschondrosteosis & Langer mesomelic dysplasia?

Answer 8

mutation in NLS of SHOX transcription factor

Short stature as SHOX required for skeletal
development