Effect of monensin on the sulfation of heparan sulfate proteoglycan from endothelial cells

✍ Scribed by Lucia O. Sampaio; Carl P. Dietrich; Patricia Colburn; Vincenzo Buonassisi; Helena B. Nader

• Publisher: John Wiley and Sons
• Year: 1992
• Tongue: English
• Weight: 852 KB
• Volume: 50
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.240500115

✦ Synopsis

Monensin is a monovalent metal ionophore that affects the intracellular translocation of secretory proteins at the level of trans-Golgi cisternae. Exposure of endothelial cells to rnonensin results in the synthesis of heparan sulfate and chondroitin sulfate with a lower degree of sulfation. The inhibition is dose dependent and affects the ratio [ 3 5 S]-s~lfate/[~H]-hexosamine of heparan sulfate from both cells and medium, with no changes in their molecular weight. By the use of several degradative enzymes (heparitinases, glycuronidase, and sulfatases) the fine structure of the heparan sulfate synthesized by control and monensin-treated cells was investigated. The results have shown that among the six heparan sulfate disaccharides there i s a specific decrease of the ones bearing a sulfate ester at the 6-position of the glucosamine moiety. All other biosynthetic steps were not affected by monensin. The results are indicative that rnonensin affects the hexosarnine C-6 sulfation, and that this sterification is the last step of the heparan sulfate biosynthesis and should occur at the trans-Golgi compartment.