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Ligatin: a cell‐surface baseplate for phosphoglycoproteins implicated in retinal cell adhesion
Author(s) -
Marchase R.B.,
Koro L.A.,
Hiller A.M.,
McClay D.R.
Publication year - 1983
Publication title -
international journal of developmental neuroscience
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.761
H-Index - 88
eISSN - 1873-474X
pISSN - 0736-5748
DOI - 10.1016/0736-5748(83)90220-4
Subject(s) - center (category theory) , anatomy , library science , medicine , chemistry , computer science , crystallography
A class of cell-surface glycoproteins from embryonic chick neural retina has been shown to interact with a filamentous baseplate protein, ligatln, via oligosaccharides containing phosphodiester-linked terminal glucose residues. The inclusion in cell adhesion assays of either e glucose-l-phosphate, a hapten effective in removing the phosphoglycoproteins from the cell surface, or soluble ligatin results in a decrease in adhesivity, suggesting a role for these proteins in retinal cell adhesion. The enzyme responsible for synthesizing the phosphooligosaccharide, a unique phosphoglucosyltransferase, transfers = glucose-l-phosphate from UDP-glucose to the glycoproteins, and is proposed to function as a controlling enzyme in the intracellular sorting of the phosphoglycoproteins for localization to the cell surface. Biochemical analyses following intracellular injection of (B32p)UDP-glucose into Aplysia ~lant neurons have demonstrated similar oligosaccharide products to those found in neural retina and suggest a wide-spread distribution for the phosphoglucosyltransferase. Autoradiographic studies support a role for this enzyme in cell-surface localization and suggest that such phosphoglycoproteins are also subject to rapid axoplasmic transport. (Supported by NIH NS-6233, EY-4480, and GM-31381).