Developmental regulation of membrane protein sorting in drosophila embryos. Shiel, Monica J., and Michael J. Caplan. Department of Cellular and Molecular Physiology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT 06510, 203-785 -6833 (T), 203-785-4951 (F)
APStracts 2:0094C, 1995.
We have examined the process of membrane protein targetting in the polarized cells of the developing Drosophila embryo. Human placental alkaline phosphatase (PLAP) is a glycosylphosphatidyl inositol (GPI) linked protein which accumulates at the apical membranes of mammalian epithelial cells. A chimeric construct composed of the transmembrane and cytosolic portions of the vesicular stomatitis virus (VSV) G protein coupled to the ectodomain of PLAP has been found to behave as a basolateral protein (Brown, D.A., B. Crise and J.K. Rose. 1989. Science 232: 34-47). The subcellular distributions of these proteins were examined in the epithelial and neuronal tissues of transgenic Drosophila embryos. In the surface ectoderm both PLAP and PLAPG were restricted to the basolateral membranes throughout development. Internal epithelia derived from the surface ectoderm accumulated PLAP at their apical surfaces, while PLAPG retained its basolateral distribution. The redistribution of PLAP from the basolateral to the apical plasma membrane was found to be coincident with the invagination of the surface epithelium to form internal structures, suggesting that the sorting pathways which function in the epithelium of the Drosophila embryo are developmentally regulated. 

Received 26 September 1994; accepted in final form 13 January
1995.
APS Manuscript Number C576-4.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 28 February 1995.