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MLN64 exhibits homology with the steroidogenic acute regulatory protein (STAR) and is over‐expressed in human breast carcinomas
Author(s) -
MoogLutz Christel,
Tomasetto Catherine,
Régnier Catherine H.,
Wendling Corinne,
Lutz Yves,
Muller Danièle,
Chenard MariePierre,
Basset Paul,
Rio MarieChristine
Publication year - 1997
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/(sici)1097-0215(19970410)71:2<183::aid-ijc10>3.0.co;2-j
Subject(s) - biology , cytoplasm , steroidogenic acute regulatory protein , cancer research , microbiology and biotechnology , gene , genetics , gene expression
The MLN64 gene, which is localized in q12‐q21 of the human chromosome 17, encodes a novel protein containing 2 distinct domains. At the N‐terminal, MLN64 exhibits a potential trans‐membrane region, while at the C‐terminal, it shares homology with the F26F4.4 protein of Caenorhabditis elegans and the steroidogenic acute regulatory (StAR) protein, a mitochondrial protein which is involved in steroid‐hormone synthesis. By comparing the C‐terminal part of these proteins, we defined a novel protein domain, which we termed SHD for “StAR Homology Domain”. Of the 93 primary invasive breast carcinomas that were examined, 14 were found to over‐express MLN64. These 14 tumors also expressed high c‐erbB‐2 transcipt levels, which were not detected in teh MLN64‐negative tumors. MLN64 mRNA and protein were specifically detected in malignant cells of breast carcinomas. MLN64 protein was localized within bundle‐like structures distributed throughout the cell cytoplasm and condensed in a perinuclear patch, suggesting an association with a specific cell compartment. When the N‐terminal part of MLN64 was deleted, MLN64 was uniformly distributed in the cell cytoplasm, indicating that N‐terminal part is involved in the specific cytoplasmic localization of MLN64. The homology between the C‐terminal part of MLN64 and the functional StAR domain (SHD) suggests that MLN64 and StAR, athough distributed in different cellular compartments, may both play a role in steroidogenesis. In this case, the high levels of MLN64 observed in some breast carcinomas could contribute to the progression of these tumors through increased intratumoral steroidogenesis. Int. J. Cancer 71:183–191, 1997. © 1997 Wiley‐Liss, Inc.