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

• DOI: 10.4161/cc.9.15.12524
• Publication Date: 2010-08-11T14:57:33Z
• Authors: Simarna Kaur; Tommy E. White; Amanda L. DiGuilio; Joseph S Glavy
• Keywords: 0301 basic medicine; Nuclear Envelope; Cell Cycle; Immunoblotting; Rats; DNA-Binding Proteins; 03 medical and health sciences; Nuclear Pore; Small Ubiquitin-Related Modifier Proteins; ATPases Associated with Diverse Cellular Activities; Animals; Humans; Carrier Proteins; HeLa Cells; Protein Binding

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 alpha-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.