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.
Department of Obstetrics and Gynecology, Nagoya University Graduate School of Medicine, 65 Tsurumai-cho, Showa-ku, Nagoya 466-8550, Japan.
Daijiro
D
Shibata
Hisao
H
Ando
Akira
A
Iwase
Tetsuro
T
Nagasaka
Akira
A
Hattori
Masafumi
M
Tsujimoto
Shigehiko
S
Mizutani
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