LYRIC/AEG-1 is targeted to different subcellular compartments by ubiquitinylation and intrinsic nuclear localization signals.
OBJECTIVE
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.


METHODS
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.
Thirkettle
Hayley J
HJ
Uro-Oncology Research Group, Cancer Research UK.
Girling
Joanne
J
Warren
Anne Y
AY
Mills
Ian G
IG
Sahadevan
Kanagasabai
K
Leung
Hing
H
Hamdy
Freddie
F
Whitaker
Hayley C
HC
Neal
David E
DE
D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D015815:Cell Adhesion Molecules / Q000235:genetics / Q000378:metabolism*; D002467:Cell Nucleus / Q000235:genetics / Q000378:metabolism*; D002478:Cells, Cultured; D015331:Cohort Studies; D003593:Cytoplasm / Q000235:genetics / Q000378:metabolism*; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D008969:Molecular Sequence Data; D041681:NIH 3T3 Cells; D019913:Nuclear Localization Signals / Q000235:genetics / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011470:Prostatic Hyperplasia / Q000235:genetics / Q000378:metabolism; D011471:Prostatic Neoplasms / Q000235:genetics / Q000378:metabolism*; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism*; D054875:Ubiquitination / Q000502:physiology*
D015815:Cell Adhesion Molecules; C483039:MTDH protein, human; D008565:Membrane Proteins; D019913:Nuclear Localization Signals; D016601:RNA-Binding Proteins; D011993:Recombinant Fusion Proteins; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins