Distribution of adipocyte-derived leucine aminopeptidase (A-LAP)/ER-aminopeptidase (ERAP)-1 in human uterine endometrium.
Adipocyte-derived leucine aminopeptidase (A-LAP, endoplasmic reticulum aminopeptidase ERAP1) is specialized to produce peptides presented on the class I major histocompatibility complex (MHC) by trimming epitopes to eight or nine residues, in addition to its enzymatic activity to degrade angiotensin II. Previously we identified placental leucine aminopeptidase (P-LAP), another member of the oxytocinase subfamily of aminopeptidases, in human uterine endometrial epithelial cells. Here we analyzed the distribution of A-LAP in human cyclic endometrium. Western blotting analysis showed that A-LAP was present in the endometrial tissue throughout the menstrual cycle. Immunohistochemical (IHC) analysis of A-LAP showed a similar distribution to that of P-LAP. A-LAP was localized predominantly in the endometrial glands and the luminal surface epithelium. However, the intracellular localization change that accompanied apocrine secretion, which was observed in P-LAP, was not shown in A-LAP. Subcellular localization of A-LAP, demonstrated by immunofluorescence, was ER in the cultured glandular epithelial cells. Our results indicate that A-LAP may fit the endometrial localization as an antigen-presenting ER aminopeptidase. Further understanding of the function(s) of A-LAP in the endometrium appear likely to yield insights into the cyclic changes during the normal endometrial cycle.
Shibata
Daijiro
D
Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
Ando
Hisao
H
Iwase
Akira
A
Nagasaka
Tetsuro
T
Hattori
Akira
A
Tsujimoto
Masafumi
M
Mizutani
Shigehiko
S
D000328:Adult; D000626:Aminopeptidases / Q000378:metabolism*; D004717:Endometrium / Q000166:cytology / Q000201:enzymology*; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008597:Menstrual Cycle; D008875:Middle Aged; D015778:Minor Histocompatibility Antigens
D015778:Minor Histocompatibility Antigens; D000626:Aminopeptidases; C464841:ERAP1 protein, human