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Sex-related differences in meprin-A, a membrane-bound mouse kidney proteinase
S T Stroupe1, S S Craig, C M Gorbea
1Department of Biochemistry, Virginia Commonwealth University, Richmond 23298.
Abstract:
To investigate the expression of meprin-A, a brush-border metalloproteinase in mouse tissues, immunohistochemical studies were conducted using a monoclonal antibody prepared against a purified form of kidney meprin-A form male mice. Kidney slices from female mice displayed markedly less immunoreactivity compared with similar preparations from male mice using this antibody. However, the specific activities of meprin-A in kidney homogenates and purified preparations of meprin-A from male and female mice were not significantly different. Western blots of kidney membrane proteins from several mouse strains indicated that the female form of meprin-A had a decreased mobility relative to the male form when subjected to sodium dodecyl sulfate-polyacrylamide gel electrophoresis; this difference could be eliminated by treatment of preparations with endoglycosidase F, which removes some asparagine-linked oligosaccharides. These data and lectin blots of membrane proteins indicate that there are differences in the glycosylation (specifically in the complex type oligosaccharides) of meprin-A in adult (8 wk old) male and female mice. Juvenile (3 wk old) male and female mice displayed similar amounts of immunohistochemical staining in kidney slices, as well as similar meprin-A electrophoretic mobilities and lectin affinities. Administration of 17 beta-estradiol to gonadectomized adult mice decreased the immunoreactivity of meprin-A in kidney slices and the electrophoretic mobility of meprin-A. These studies indicate that estrogens affect posttranslational modifications of meprin-A.
Insights
Sex hormones influence meprin-A glycosylation in mice. Estrogen administration altered meprin-A
Area of Science:
- Biochemistry
- Molecular Biology
- Immunology
Background:
- Meprin-A is a metalloproteinase found in mouse brush-border membranes.
- Previous studies suggest sex-based differences in protein expression and activity.
Purpose of the Study:
- To investigate sex-specific expression and posttranslational modifications of meprin-A in mouse kidneys.
- To determine the role of sex hormones in regulating meprin-A glycosylation.
Main Methods:
- Immunohistochemistry using a monoclonal antibody against mouse kidney meprin-A.
- Western blotting and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of kidney membrane proteins.
- Endoglycosidase F treatment and lectin blotting to analyze glycosylation patterns.
- Hormonal administration studies in gonadectomized mice.
Main Results:
- Female mice showed less meprin-A immunoreactivity in kidney slices compared to males, despite similar enzyme activity.
- Western blots revealed decreased electrophoretic mobility of meprin-A in females, linked to differences in N-linked oligosaccharides.
- These glycosylation differences were absent in juvenile mice but present in adults.
- Administration of 17 beta-estradiol to adult mice reduced meprin-A immunoreactivity and altered its electrophoretic mobility.
Conclusions:
- Adult male and female mice exhibit distinct glycosylation patterns of meprin-A, specifically in complex-type oligosaccharides.
- Estrogens play a significant role in modulating these posttranslational modifications of meprin-A.
- These findings highlight sex-based hormonal regulation of protein glycosylation in the kidney.