Endosomal Recycling Regulates Anthrax Toxin Receptor 1/Tumor Endothelial Marker 8-Dependent Cell Spreading

• Type of Material: Article
• Authors: Jingsheng Gu, Emory University; Victor Faundez, Emory University; Erica Werner, Emory University
• Language: English
• Date: 2010-07-15
• Publisher: Elsevier: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: © 2010 Elsevier Inc. All rights reserved.
• Final Published Version (URL): http://dx.doi.org/10.1016/j.yexcr.2010.03.026
• Title of Journal or Parent Work: Experimental Cell Research
• ISSN: 0014-4827
• Volume: 316
• Issue: 12
• Start Page: 1946
• End Page: 1957
• Grant/Funding Information: National Cancer Institute : NCI; This work was supported by grants from the National Institutes of Health to E.W. (CA127136) and V.F. (NS42599 and GM077569).; National Institute of General Medical Sciences : NIGMS; National Institute of Neurological Disorders and Stroke : NINDS
• Keywords: cell spreading; Rab11; TEM8; anthrax toxin; Transferrin Receptor
• Research Categories: Biology, Cell

Abstract

Mechanisms for receptor-mediated anthrax toxin internalization and delivery to the cytosol are well understood. However, far less is known about the fate followed by anthrax toxin receptors prior and after cell exposure to the toxin. We report that Anthrax Toxin Receptor 1/Tumor Endothelial Marker 8 (TEM8) localized at steady state in Rab11a-positive and transferrin receptor-containing recycling endosomes. TEM8 followed a slow constitutive recycling route of ∼30 minutes as determined by pulsed surface biotinylation and chase experiments. A Rab11a dominant negative mutant and Myosin Vb tail expression impaired TEM8 recycling by sequestering TEM8 in intracellular compartments. Sequestration of TEM8 in intracellular compartments with monensin coincided with increased TEM8 association with a multi-protein complex isolated with antibodies against transferrin receptor. Addition of the cell-binding component of anthrax toxin, Protective Antigen, reduced TEM8 half-life from seven to three hours, without preventing receptor recycling. Pharmacological and molecular perturbation of recycling endosome function using monensin, dominant negative Rab11a, or myosin Vb tail, reduced PA-binding efficiency and TEM8-dependent cell spreading on PA-coated surfaces without affecting toxin delivery to the cytosol. These results indicate that the intracellular fate of TEM8 differentially affect its cell adhesion and cell intoxication functions.