Open AccessCell cycle‐related variation in subcellular localization of eIF3e/INT6 in human fibroblasts
Author(s) -
Watkins S. J.,
Norbury C. J.
Publication year - 2004
Publication title -
cell proliferation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.647
H-Index - 74
eISSN - 1365-2184
pISSN - 0960-7722
DOI - 10.1111/j.1365-2184.2004.00305.x
Subject(s) - eif4a1 , protein subunit , biology , cytoplasm , initiation factor , proteasome , subcellular localization , microbiology and biotechnology , eukaryotic translation initiation factor 4 gamma , nuclear localization sequence , cop9 signalosome , nucleus , eukaryotic translation , cell nucleus , translation (biology) , messenger rna , biochemistry , gene , enzyme , protease , peptide hydrolases
Abstract. The Int‐6 gene is a site of mouse mammary tumour virus (MMTV) integration in murine tumours and INT6 protein has been identified independently as a subunit (eIF3e) of the eukaryotic translation initiation factor eIF3. In addition, the protein can interact with two other multi‐subunit complexes: the COP9 signalosome (CSN) and the proteasome. The role of INT6 in tumourigenesis is nonetheless currently unclear. Here, using immunofluorescence microscopy, we show that eIF3e/INT6 is localized in part to the nucleus, while other eIF3 components are cytoplasmic. Primary human fibroblasts, but not their transformed counterparts, showed reduced nuclear INT6 staining in some cells, and this reduction was maximal in early S phase. This variation in eIF3e/INT6 may indicate regulated shuttling between cellular compartments and would be consistent with the presence of a nuclear export signal as well as a nuclear localization signal in the protein sequence. Loss of regulation of eIF3e/INT6 redistribution may therefore be a significant feature of malignancy in human cells.