Identification of carbonic anhydrase XII as the membrane isozyme expressed in the normal human endometrial epithelium

• Published in: Molecular human reproduction Vol. 6; no. 1; pp. 68 - 74
• Main Authors: Karhumaa, P., Parkkila, S., Türeci, Ö., Waheed, A., Grubb, J.H., Shah, G., Parkkila, A.-K., Kaunisto, K., Tapanainen, J., Sly, W.S., Rajaniemi, H.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01-01-2000; Oxford Publishing Limited (England)
• Subjects: Animals; bicarbonate; Biological and medical sciences; Blotting, Northern; carbonic anhydrase; Carbonic Anhydrases - biosynthesis; Carbonic Anhydrases - genetics; Carbonic Anhydrases - immunology; Carbonic Anhydrases - isolation & purification; Cell Membrane - metabolism; CHO Cells; Cricetinae; Endometrium - enzymology; Endometrium - pathology; Epithelium - enzymology; Female; Fluorescent Antibody Technique; Fundamental and applied biological sciences. Psychology; Hormone metabolism and regulation; Humans; immunohistochemistry; Isoelectric Focusing; Isoenzymes - biosynthesis; Isoenzymes - genetics; Isoenzymes - immunology; Isoenzymes - isolation & purification; Mammalian female genital system; uterus; Vertebrates: reproduction; Human; Immunohistochemistry; Purification; Enzyme; Gel electrophoresis; Isozyme; Lyases; Gene expression; Hydrogencarbonates; Northern blotting; Uterus; Affinity chromatography; Female genital system; Immunoblotting assay; pH; Female; Carbonate dehydratase; Carbon-oxygen lyases; Endometrium; Hydro-lyases
• ISSN: 1360-9947; 1460-2407; 1460-2407
• DOI: 10.1093/molehr/6.1.68

Although previous studies demonstrated carbonic anhydrase (CA) activity in the human endometrium, the CA isozyme(s) responsible for this activity has not been established. In this report, we provide the first evidence that the CA isozyme XII, a recently identified transmembrane isozyme that is expressed in normal kidney and greatly overexpressed in some renal cancers, is present in endometrium. We show by immunohistochemistry that CA XII is expressed in the basolateral plasma membrane of epithelial cells of normal human endometrium. Expression of CA XII in uterus was confirmed by Northern blotting. Detergent-solubilized CA XII was isolated from human endometrium by inhibitor affinity chromatography and characterized by isoelectric focusing and Western blot as a polypeptide with a pI of 6.3. The high expression of CA XII in the endometrial epithelium suggests that it may be functionally linked to the pH-dependent events in spermatozoa that precede fertilization. Its basolateral location and extracellular active site could also allow it to influence the morphological changes in endometrium that occur during the menstrual cycle.