Quantitative analysis of glomerular basement membrane glycosaminoglycans and evidence for their binding to adjacent cell membrane lipids
✍ Scribed by Van-Yu Wu; I-I.C. Chiu; Margo Panush Cohen
- Publisher
- Elsevier Science
- Year
- 1985
- Tongue
- English
- Weight
- 544 KB
- Volume
- 145
- Category
- Article
- ISSN
- 0003-2697
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✦ Synopsis
Glycosaminoglycans (GAG) were isolated from rat renal glomerular basement membranes subjected to extraction with detergents, and were quantitatively analyzed using a recently described competitive binding assay that is specific for and sensitive to microgram amounts of chondroitin and heparan sulfate. Whereas crude membranes prepared by osmotic lysis contained only 6 pg/mg dry wt, subsequent treatment with Triton X-100 or deoxycholate (DOC) increased measureable GAG to about I7 and 34 pg/mg, respectively. Repeated freezing and thawing of isolated gfomeruli also augmented measurable GAG content in subsequently osmotically lysed membranes to levels observed in T&on-treated membranes. DOC solubilized = 15-20% of membrane-associated GAG. Chondroitin sulfate comprised = 30% of total GAG, and all of the chondroitin sulfate but only 10% of the heparan sulfate was extracted from the insoluble matrix by DGC. The findings indicate that GAG content of glomerular basement membrane is several-fold higher than previously estimated, and that a substantial portion is bound to cell membrane lipids. The results further suggest two populations of GAG in basement membrane; one that is intercalated with adjacent cell membranes, and another that remains as an integral component of the insoluble matrix after detergent extraction. o 1985 Academic Press, Inc.