Protein transfer into and out of the nucleus occurs through the nuclear pore complex (NPCs). Karyopherin, a cytosolic, heterodimeric protein complex consisting of alpha and beta subunits, is responsible for targeting proteins with nuclear localization signals to the nuclear pore complex. NPI-1 (nucleoprotein interactor-1, hSRP-1) is the alpha subunit of karyopherin, which acts as the receptor for the targeted protein’s nuclear localization signal. Both subunits of karyopherin are required for protein docking at the NPC; the alpha subunit binds the substrate and the beta subunit acts as an adaptor. Two other proteins, p10 and the GTPase Ran, are also required for the translocation of docked proteins to the nucleus. The karyopherin dimer dissociates during import, a process mediated by RanGTP, which binds to karyopherin beta and promotes the release of both subunits from the docking site. The alpha subunit and imported substrate enter the nucleus and accumulate in the nucleoplasm, while the beta subunit accumulates at the NPC. The 60 kD NPI-1 was first identified as the human homolog of the yeast SRP-1 protein, by its interaction with influenza virus nucleoprotein. NPI-1 has also been observed in its interaction with Epstein-Barr virus (EBV) nuclear antigen-1 (EBNA) and STAT-1, both of which are transported into the nucleus.

Suitable for use in Immunoprecipitation, Immunofluorescence, FLISA and Western Blot. Other applications have not been tested

Optimal dilutions to be determined by the researcher.

Store product at 4°C in the dark. DO NOT FREEZE! Stable at 4°C for 12 months after receipt as an undiluted liquid. Dilute required amount only prior to immediate use. Further dilutions can be made in assay buffer. Caution: MaxLight™650 conjugates are sensitive to light. For maximum recovery of product, centrifuge the original vial prior to removing the cap.

Note: Applications are based on unconjugated antibody.

GST fusion protein.

Supplied as a liquid in PBS, pH 7.2. No preservatives added. Labeled with MaxLight™650.

Purified by Protein A affinity chromatography.

Recognizes human NPI-1 (nucleoprotein interactor-1, karyopherin alpha 1, hSRP1) protein. On Western blots, it identifies a band at ~60kD. Reactivity has been confirmed with human HeLa and MDBK cell lysates. Species Crossreactivity: mouse