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transportin-2; karyopherin beta-2b (TNPO2)
Function:
- role in nuclear protein import as nuclear transport receptor
- serves as receptor for nuclear localization signals (NLS) in cargo substrates
- thought to mediate docking of the importin/substrate complex to the nuclear pore complex (NPC) through binding to nucleoporin
- the complex is subsequently translocated through the pore by an energy requiring, Ran-dependent mechanism
- at the nucleoplasmic side of the NPC, Ran binds to importin, the importin/substrate complex dissociates & importin is re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran
- the directionality of nuclear import is thought to be conferred by an asymmetric distribution of the GTP- & GDP- bound forms of Ran between the cytoplasm & nucleus (putative)
Structure:
- belongs to the importin beta family
- contains 13 HEAT repeats
- contains 1 importin N-terminal domain
Compartment:
- cytoplasm (putative), nucleus
Alternative splicing: named isoforms=2
Related
importin beta-2 subunit (karyopherin beta-2 subunit, KPNB2, transportin-1, M9 region interaction protein, MIP, TNPO1, MIP1, TRN)
General
HEAT repeat-containing protein (HEATR)
nuclear protein
transportin (TNPO)
Properties
SIZE: entity length = 897 aa
MW = 101 kD
COMPARTMENT: cytoplasm
cell nucleus
MOTIF: Importin N-terminal {31-99}
HEAT repeat {121-159}
HEAT repeat {167-205}
HEAT repeat {208-246}
HEAT repeat {249-287}
HEAT repeat {292-330}
HEAT repeat {389-427}
HEAT repeat {430-468}
HEAT repeat {472-510}
HEAT repeat {513-551}
HEAT repeat {556-596}
HEAT repeat {659-697}
HEAT repeat {700-738}
HEAT repeat {741-780}
Database Correlations
OMIM 603002
UniProt O14787
PFAM correlations
Entrez Gene 30000
References
UniProt :accession O14787