Distinct heparan sulfate compositions in wild-type and pipe-mutant eggshell matrix.
Spatial information embedded in the extracellular matrix establishes the dorsoventral polarity of the Drosophila embryo through the ventral activity of a serine protease cascade. Pipe is a Golgi-localized protein responsible for generating this spatial information during oogenesis through sulfation of unknown glycans. Although Pipe has sequence homology to glycosaminoglycan 2-O-sulfotransferases, its activity and authentic substrates have not been demonstrated and genetic evidence has argued against a role for glycosaminoglycans in dorsoventral polarity establishment. Here, direct examination of matrix glycosaminoglycans demonstrates that pipe-mutant matrix shows decreased tri-sulfated heparan sulfate compared to wild-type matrix, with correspondingly increased 2-O-sulfated heparan sulfate. Chondroitin sulfate was not detected in this matrix. These results suggest that Pipe promotes 6-O- and/or N-sulfation of heparan sulfate but is not required for heparan sulfate 2-O-sulfation. We discuss the possible significance of these unexpected findings and how they might be reconciled with the genetic data.
Park
Youmie
Y
Department of Chemistry and Chemical Biology, and Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, New York, USA.
Zhang
Zhenqing
Z
Linhardt
Robert J
RJ
LeMosy
Ellen K
EK
D000818:Animals; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000196:embryology* / Q000201:enzymology / Q000235:genetics; D047108:Embryonic Development; D005109:Extracellular Matrix / Q000201:enzymology; D006025:Glycosaminoglycans / Q000378:metabolism; D006497:Heparan Sulfate / Q000378:metabolism*; D010063:Ovum / Q000201:enzymology; D015238:Sulfotransferases / Q000235:genetics / Q000378:metabolism*
D029721:Drosophila Proteins; D006025:Glycosaminoglycans; D006497:Heparan Sulfate; D015238:Sulfotransferases; C115847:pip protein, Drosophila