Functional properties of membrane-bound mucins MUC1 and MUC4 in the oral cavity
Date
2003
DOI
Authors
Li, Xiaojing
Version
OA Version
Citation
Abstract
MUCl and MUC4 are two membrane-bound mucins which are expressed on
many epithelial surfaces throughout the body including the oral cavity. The functions of
these mucins in normal cells are diverse, ranging from physiological roles in cell growth,
differentiation, uterine embryo implantation, epithelial protection, bacterial attachment
and signal transduction. In malignant cells, these mucins assume pathological roles in the
masking of recognition sites for natural killer cells and promotion of tumor cell
metastasis. Little is known, however, concerning the functions of these mucins in the oral
cavity and the aims of this study were to (1) investigate the biosynthetic processing of
MUCl and MUC4, (2) elucidate the protective functions of these mucins in oral
epithelial cells in a model of bacterial injury and (3) to investigate the regulation of
MUC 1 expression modulated by proinflammatory mediators and oral microorganisms.
A series of MUCl and MUC4 expression constructs was prepared and used to
investigate the biosynthetic processing of these two mucins. It was found that MUCl is
cleaved into two subunits during the secretory pathway at the sequence FRPG/SVVV.
Interestingly, nearly equal amounts of both full length uncleaved MUCl and the cleaved
extracellular subunit of MUCl were found in COS-7 cells, suggesting that the cleavage
event is part of a long term process, which may occur at different locations during
secretion. In contrast, no evidence was found for a similar cleavage event during the
biosynthesis of MUC4. This was surprising because the rat homologue of MUC4,
SMC/Muc4 has been shown to undergo cleavage at the sequence Gly-Asp-Pro-His ... [TRUNCATED]
Description
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please log in with a valid BU account to access and click Download. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.
Thesis (D.Sc.D.)--Boston University Henry M. Goldman School of Dental Medicine, 2003 (Periodontology and Oral Biology).
Includes bibliography (leaves 146-184).
Thesis (D.Sc.D.)--Boston University Henry M. Goldman School of Dental Medicine, 2003 (Periodontology and Oral Biology).
Includes bibliography (leaves 146-184).
License
This work is protected by copyright. Downloading is restricted to the BU community. If you are the author of this work and would like to make it publicly available, please contact open-help@bu.edu.