University of Oulu

Myllymäki, S., Manninen, A. (2019) Cell surface expression of integrin β4-subunit in the absence of α6-subunit. Matters, Mar 13th, 2019. doi:10.19185/matters.201902000007

Cell surface expression of integrin β4-subunit in the absence of α6-subunit

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Author: Myllymäki, Satu-Marja1; Manninen, Aki1
Organizations: 1Oulu Center for Cell-Matrix Research, Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu, Developmental Biology Program, Institute of Biotechnology, University of Helsinki; Oulu Center for Cell-Matrix Research, Faculty of Biochemistry and Molecular Medicine, Biocenter Oulu, University of Oulu
Format: article
Version: published version
Access: open
Online Access: PDF Full Text (PDF, 0.6 MB)
Persistent link: http://urn.fi/urn:nbn:fi-fe2019042913476
Language: English
Published: Sciencematters, 2019
Publish Date: 2019-04-29
Description:

Abstract

Laminin-rich basement membrane (BM) guides epithelial cell polarity, regulates epithelial cell behavior and maintains the integrity of epithelial tissues. αβ1- and α6β4-integrins both contribute to laminin adhesion and signaling via the assembly of integrin adhesion complexes that help to orient the apico-basal polarity axis. β4-integrin differs from other integrin subunits due to its large cytoplasmic domain that connects to cellular intermediate filament (IF) networks in specialized adhesions called hemidesmosomes (HD). β4-integrin is only known to form a heterodimer with the α6-subunit. In normal tissues, β4-integrin is expressed in cells that also express the α6-subunit. However, in most cells analyzed, β4-integrin is expressed in large excess over α6-integrin and in some tumor cells, β4-integrin appears to promote tumorigenic signaling despite loss of HDs formation. The fate of free β4-subunit and its potential functions in cells have not been extensively studied. Here, we have studied subcellular localization and potential surface delivery of β4-integrin in the absence of its heterodimer partner α6. We provide evidence that a significant fraction of β4-subunit can reach the cell surface without α6-subunit. We also report that β4 is cleaved at its extracellular domain to produce a membrane-bound proteolytic product with an intact cytoplasmic domain. The processed β4-integrin did not co-precipitate with α6-subunit. Taken together, our data suggest that β4-integrin might have functions that are independent of heterodimer formation.

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Series: Matters
ISSN: 2297-8240
ISSN-E: 2297-8240
ISSN-L: 2297-8240
Volume: Mar 13th
DOI: 10.19185/matters.201902000007
OADOI: https://oadoi.org/10.19185/matters.201902000007
Type of Publication: A1 Journal article – refereed
Field of Science: 1182 Biochemistry, cell and molecular biology
Subjects:
Funding: This work was funded by Academy of Finland (251314, 135560, 263770, and 140974 /AM).
Academy of Finland Grant Number: 251314
135560
263770
140974
Detailed Information: 251314 (Academy of Finland Funding decision)
135560 (Academy of Finland Funding decision)
263770 (Academy of Finland Funding decision)
140974 (Academy of Finland Funding decision)
Copyright information: © The Authors and Matters. Creative Commons 4.0. This observation is distributed under the terms of the Creative Commons Attribution 4.0 International License.
  https://creativecommons.org/licenses/by/4.0/