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J Biol Chem. 2014 May 9;289(19):13445-60. doi: 10.1074/jbc.M113.546754. Epub 2014 Mar 24.

Syntenin-1 and ezrin proteins link activated leukocyte cell adhesion molecule to the actin cytoskeleton.

Author information

1
From the Nanobiophysics, MIRA Institute for Biomedical Technology and Technical Medicine and MESA+ Institute for Nanotechnology, University of Twente, 7500AE Enschede, The Netherlands.

Abstract

Activated leukocyte cell adhesion molecule (ALCAM) is a type I transmembrane protein member of the immunoglobulin superfamily of cell adhesion molecules. Involved in important pathophysiological processes such as the immune response, cancer metastasis, and neuronal development, ALCAM undergoes both homotypic interactions with other ALCAM molecules and heterotypic interactions with the surface receptor CD6 expressed at the T cell surface. Despite biochemical and biophysical evidence of a dynamic association between ALCAM and the actin cytoskeleton, no detailed information is available about how this association occurs at the molecular level. Here, we exploit a combination of complementary microscopy techniques, including FRET detected by fluorescence lifetime imaging microscopy and single-cell force spectroscopy, and we demonstrate the existence of a preformed ligand-independent supramolecular complex where ALCAM stably interacts with actin by binding to syntenin-1 and ezrin. Interaction with the ligand CD6 further enhances these multiple interactions. Altogether, our results propose a novel biophysical framework to understand the stabilizing role of the ALCAM supramolecular complex engaged to CD6 during dendritic cell-T cell interactions and provide novel information on the molecular players involved in the formation and signaling of the immunological synapse at the dendritic cell side.

KEYWORDS:

ALCAM; Actin; Atomic Force Microscopy; Cell Adhesion; Cytoskeleton; FRET-FLIM; Fluorescence Resonance Energy Transfer (FRET); Single-cell Force Spectroscopy

PMID:
24662291
PMCID:
PMC4036352
DOI:
10.1074/jbc.M113.546754
[Indexed for MEDLINE]
Free PMC Article

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