Identification of a novel centrosomal protein CrpF46 involved in cell cycle progression and mitosis

A novel centrosome-related protein Crp(F46) was detected using a serum F46 from a patient suffering from progressive systemic sclerosis. We identified the protein by immunoprecipitation and Western blotting followed by tandem mass spectrometry sequencing. The protein Crp(F46) has an apparent molecular mass of similar to 60 kDa, is highly homologous to a 527 amino acid sequence of the C-terminal portion of the protein Golgin-245, and appears to be a splice variant of Golgin-245. Immunofluorescence microscopy of synchronized HeLa cells labeled with an anti-Crp(F46) monoclonal antibody revealed that Crp(F46) localized exclusively to the centrosome during interphase, although it dispersed throughout the cytoplasm at the onset of mitosis. Domain analysis using Crp(F46) fragments in GFP-expression vectors transformed into HeLa cells revealed that centrosomal targeting is conferred by a C-terminal coiled-coil domain. Antisense Crp(F46) knockdown inhibited cell growth and proliferation and the cell cycle typically stalled at S phase. The knockdown also resulted in the formation of poly-centrosomal and multinucleate cells, which finally became apoptotic. These results suggest that Crp(F46) is a novel centrosome-related protein that associates with the centrosome in a cell cycle-dependent manner and is involved in the progression of the cell cycle and M phase mechanism. (C) 2008 Elsevier Inc. All rights reserved.