Anti-KPNA2 Antibody Picoband®

Importin subunit alpha-2 is a protein that in humans is encoded by the KPNA2 gene. The import of proteins into the nucleus is a process that involves at least 2 steps. The first is an energy-independent docking of the protein to the nuclear envelope and the second is an energy-dependent translocation through the nuclear pore complex. Imported proteins require a nuclear localization sequence (NLS) which generally consists of a short region of basic amino acids or 2 such regions spaced about 10 amino acids apart. Proteins involved in the first step of nuclear import have been identified in different systems. These include the Xenopus protein importin and its yeast homolog, SRP1 (a suppressor of certain temperature-sensitive mutations of RNA polymerase I in Saccharomyces cerevisiae), which bind to the NLS. KPNA2 protein interacts with the NLSs of DNA helicase Q1 and SV40 T antigen and may be involved in the nuclear transport of proteins. KPNA2 also may play a role in V (D) J recombination.

Functions in nuclear protein import as an adapter protein for nuclear receptor KPNB1. Binds specifically and ly to substrates containing either a simple or bipartite NLS motif. Docking of the importin/substrate complex to the nuclear pore complex (NPC) is mediated by KPNB1 through binding to nucleoporin FxFG repeats 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 importin-beta and the three components separate and importin-alpha and -beta are re-exported from the nucleus to the cytoplasm where GTP hydrolysis releases Ran from importin. The ionality 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.

1. Cuomo CA, Kirch SA, Gyuris J, Brent R, Oettinger MA (Jun 1994) . Rch1, a protein that specifically interacts with the RAG-1 recombination-activating protein. Proceedings of the National Academy of Sciences of the United States of America. 91 (13) : 6156–60. 2. Weis K, Mattaj IW, Lamond AI (May 1995) . Identification of hSRP1 alpha as a functional receptor for nuclear localization sequences. Science. 268 (5213) : 1049–53.

Store at -20°C for one year from date of receipt. After reconstitution, at 4°C for one month. It can also be aliquotted and stored frozen at -20°C for six months. Avoid repeated freeze-thaw cycles.