IDENTIFICATION OF THE HUMAN INTESTINAL RECEPTOR FOR E. COLI HEAT - STABLE ENTEROTOXIN

Abstract

Enterotoxigenic E. coli that elaborate heat-stable enterotoxin (ST_a) are a world-wide cause of diarrheal disease. We have previously demonstrated that ST_a, a polypeptide able to induce intestinal secretion, binds to a specific receptor in human intestine. In order to characterize this receptor, we used a calcium precipitation technique to prepare brush border membranes (BBM) from human small intestine. BBM were incubated with radiolabeled ST_a (4-Tyr-¹²⁵I-ST_a) in the presence and absence of excess native ST_a. Radiolabeled ST_a was crosslinked to BBM using the photoaffinity agent N-hydroxysuccinimidyl-4-azidobenzoate. These BBM, with the ST_a receptor covalently crosslinked to radiolabeled ST_a, were subjected to SDS-PAGE and autoradiography. Two proteins of M_r 66,000 and 98,000 were highly radiolabeled by this technique. Crosslinking of radiolabeled ST_a to these proteins was markedly diminished in the presence of unlabeled ST_a. These same proteins were specifically crosslinked in specimens from 25 different patients as well as in multiple specimens obtained throughout the jejunum and ileum of 2 different patients. We conclude that these proteins are probably major binding components of the human intestinal ST_a receptor.

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account

Continue with Google

Continue with ORCiD