TheDrosophilaRhomboid Protein Is Concentrated in Patches at the Apical Cell Surface

Autor: Sturtevant, Mark A., Roark, Margaret, O'Neill, Jason W., Biehs, Brian, Colley, Nansi, Bier, Ethan
Zdroj: Developmental Biology; March 1996, Vol. 174 Issue: 2 p298-309, 12p
Abstrakt: Patterned expression of theDrosophila rhomboid(rho) gene is thought to promote signaling by the EGF receptor (EGF-R) in specific cell types. In this report we examine the subcellular localization of the Rhomboid protein (Rho) which is predicted to be an integral membrane protein. At the light level, immunocytochemical staining for Rho reveals a small number of large patches (or plaques) at or near the apical cell surface. In some cells Rho plaques colocalize with Armadillo at adherens junctions, while in other cells plaques are only found basal to the adherens junction. Immunoelectron microscopy reveals that Rho plaques are composed of a highly localized patch of plasma membrane and a densely staining underlying structure. Concentration of Rho in distinct plaques depends on a balance of synthesis and membrane recycling since increasing the amount ofrhoexpression or blocking membrane recycling leads to more uniform cell surface labeling. A limiting cellular component also appears to be required for concentrating Rho in plaques. We discuss clustering of Rho in plasma membrane patches with respect to the proposed role of Rho in promoting EGF-R signaling.
Databáze: Supplemental Index