FEATURES

FAMILY

DESCRIPTION

Also known as TNPO1_HUMAN, TNPO1, KPNB2, MIP1, TRN. Functions in nuclear protein import as nuclear transport receptor. Serves as receptor for nuclear localization signals (NLS) in cargo substrates (PubMed:24753571). Is thought to mediate docking of the importin/substrate complex to the nuclear pore complex (NPC) through binding to nucleoporin and 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 the importin, the importin/substrate complex dissociates and 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- and GDP-bound forms of Ran between the cytoplasm and nucleus (By similarity). Involved in nuclear import of M9-containing proteins. In vitro, binds directly to the M9 region of the heterogeneous nuclear ribonucleoproteins (hnRNP), A1 and A2 and mediates their nuclear import. Appears also to be involved in hnRNP A1/A2 nuclear export. Mediates the nuclear import of ribosomal proteins RPL23A, RPS7 and RPL5. Binds to a beta-like import receptor binding (BIB) domain of RPL23A. In vitro, mediates nuclear import of H2A, H2B, H3 and H4 histones, and SRP19 (By similarity). Mediates nuclear import of ADAR/ADAR1 isoform 1 and isoform 5 in a RanGTP-dependent manner (PubMed:19124606, PubMed:24753571)., (Microbial infection) In case of HIV-1 infection, binds and mediates the nuclear import of HIV-1 Rev. Identified in a complex that contains TNPO1, RAN and RANBP1 (PubMed:9428644). Binds HNRPA1, HNRPA2, HNRNPDL, RPL23A, RPS7, RPL5, RAN and SRP19. Interacts with H2A, H2B, H3 and H4 histones (By similarity). Interacts with isoform 1 and isoform 5 of ADAR/ADAR1 (via DRBM 3 domain) (PubMed:19124606, PubMed:24753571). Interacts with SNAI1 (via zinc fingers); the interaction mediates SNAI1 nuclear import (PubMed:19386897). Interacts with SNAI2 (via zinc fingers) (PubMed:19386897).

EXTERNAL LINKS

TNPO1

Transportin-1

TNPO1

Molecular Synopsis