Dally-like protein, a new Drosophila glypican with expression overlapping with wingless

Proteoglycans, the molecules of extracellular matrix, carry a highly negati ve charge due to their glycosaminoglycan (GAG) chains and large volumes. Th ey were considered to play a secondary role in activities like cell divisio n, adhesion, blood coagulation, etc. until the importance of their sugar ch ains in the fibroblast growth factor (FGF) signalling was discovered (Scien ce 252 (1991) 1705; Cell 64 (1991) 841). Studies of mutations in the genes sugarless(sgl) and sulfateless (sfl) have proved that the proteoglycans inv olved in Wg signalling contain heparan sulfate GAG chains (Development 124 (1997) 2623; Development 124 (1997) 3055; Development 124 (1997) 3565; Deve lopment 126 (1999) 3715). This has led to the attribution of specific funct ions to these molecules (J. Cell Biol. 148 (2000) 227). The Glypican family of heparan sulfate proteoglycans (HSPGs) is characterized by core proteins with conserved cysteine residues and attachment to the cell surface by a g lycosylphosphatidyl inositol (GPI) anchor. This may lead to endocytic pathw ays that are different from other HSPGs, higher lateral mobility and possib le apical localisation in a cell (Proc. Natl. Acad. Sci, USA 85 (1988) 9557 ). Variations in their HS contents may effect binding properties and locali sation (J. Cell Biol. 124 (1994) 149; J. Cell Biol. 132 (1996) 487), thus s pecialising each member for a unique biological function. Glypicans play im portant roles in morphogenetic pathways, e.g. human glypican 3 (GPC3) is mu tated in Simpson-Golabi-Behmel syndrome making an individual prone to tumou rs (Nat. Genet. 12 (1996) 241). Daily, the first Drosophila member of the f amily, is essential for the wingless and decapentaplegic signalling pathway s (Development 121 (1995) 3687; Development 124 (1997) 4113). Here, we repo rt a new Drosophila glypican, daily-like protein (dlp) with all the feature s of a glypican. Based on expression studies we report its colocalisation w ith Wg. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.