LYRIC/AEG-1 Is Targeted to Different Subcellular Compartments by Ubiquitinylation and Intrinsic Nuclear Localization Signals

• Published in: Clinical cancer research 2009-05, Vol.15 (9), p.3003-3013
• Main Authors: THIRKETTLE, HayleyJ, GIRLING, Joanne, WARREN, Anne Y, MILLS, Ian G, SAHADEVAN, Kanagasabai, LEUNG, Hing, HAMDY, Freddie, WHITAKER, Hayley C, NEAL, David E
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Antineoplastic agents; Biological and medical sciences; Blotting, Western; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - metabolism; Cell Nucleus - genetics; Cell Nucleus - metabolism; Cells, Cultured; Cohort Studies; Cytoplasm - genetics; Cytoplasm - metabolism; distribution; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Humans; Immunoenzyme Techniques; Immunoprecipitation; Male; Medical sciences; Mice; Molecular Sequence Data; NIH 3T3 Cells; Nuclear Localization Signals - genetics; Nuclear Localization Signals - metabolism; Pharmacology. Drug treatments; Polymerase Chain Reaction; prostate cancer; Prostatic Hyperplasia - genetics; Prostatic Hyperplasia - metabolism; Prostatic Neoplasms - genetics; Prostatic Neoplasms - metabolism; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Sequence Deletion; Sequence Homology, Amino Acid; Subcellular Fractions - metabolism; Ubiquitination - physiology; ubiquitinylation
• ISSN: 1078-0432; 1557-3265
• DOI: 10.1158/1078-0432.CCR-08-2046

Purpose: LYRIC/AEG-1 has been reported to influence breast cancer survival and metastases, and its altered expression has been found in a number of cancers. The cellular function of LYRIC/AEG-1 has previously been related to its subcellular distribution in cell lines. LYRIC/AEG-1 contains three uncharacterized nuclear localization signals (NLS), which may regulate its distribution and, ultimately, function in cells. Experimental Design: Immunohistochemistry of a human prostate tissue microarray composed of 179 prostate cancer and 24 benign samples was used to assess LYRIC/AEG-1 distribution. Green fluorescent protein-NLS fusion proteins and deletion constructs were used to show the ability of LYRIC/AEG-1 NLS to target green fluorescent protein from the cytoplasm to the nucleus. Immunoprecipitation and Western blotting were used to show posttranslational modification of LYRIC/AEG-1 NLS regions. Results: Using a prostate tissue microarray, significant changes in the distribution of LYRIC/AEG-1 were observed in prostate cancer as an increased cytoplasmic distribution in tumors compared with benign tissue. These differences were most marked in high grade and aggressive prostate cancers and were associated with decreased survival. The COOH-terminal extended NLS-3 (amino acids 546-582) is the predominant regulator of nuclear localization, whereas extended NLS-1 (amino acids 78-130) regulates its nucleolar localization. Within the extended NLS-2 region (amino acids 415-486), LYRIC/AEG-1 can be modified by ubiquitin almost exclusively within the cytoplasm. Conclusions: Changes in LYRIC/AEG-1 subcellular distribution can predict Gleason grade and survival. Two lysine-rich regions (NLS-1 and NLS-3) can target LYRIC/AEG-1 to subcellular compartments whereas NLS-2 is modified by ubiquitin in the cytoplasm.