The discovery of a Werner helicase interacting protein (WHIP) association with the nuclear pore complex

The gateway for molecular trafficking between the cytoplasm and the nucleus is the Nuclear Pore Complex (NPC). Through mass spectral analysis of the isolated Nuclear Pore Nup107-160 subcomplex, we discovered an in vivo interaction with Werner's Helicase Interacting Protein 1, (WRNIP1 or WHIP). WHIP was originally identified as a binding partner of Werner protein (WRN), which functions to maintain genome stability and is responsible for the progeria disease, Werner syndrome. We established the reciprocal isolation of Nup107 by α-WHIP. WHIP was found in purified Nuclear Envelope (NE) fractions treated with DNase/RNase/Heparin. We demonstrated by immunofluorescence microscopy that WHIP is located at the nuclear rim as well as punctate regions in the nuclear matrix. Ultimately, synchronized cells show a dynamic association between WHIP and the Nup107-160 subcomplex through the cell cycle without an interaction with WRN. We thus identify WHIP as a partner/component of the NE/NPC and set forth to investigate a role for the protein positioned at the NPC.