N-terminal nesprin-2 variants regulate β-catenin signalling

Autor: Qiuping, Zhang, Rose-Marie, Minaisah, Elisa, Ferraro, Chen, Li, Lauren J, Porter, Can, Zhou, Fang, Gao, Junyi, Zhang, Dipen, Rajgor, Flavia, Autore, Catherine M, Shanahan, Derek T, Warren
Rok vydání: 2015
Předmět:
HDF
human dermal fibroblast cell
Transcription
Genetic
CHD
calponin homology domain
ESC
embryonic stem cells
Nerve Tissue Proteins
Cell Line
Mice
VSMC
human vascular smooth muscle cell
HUVEC
human umbilical vein endothelial cells
Animals
Humans
Protein Isoforms
beta Catenin
Scaffold protein
Cell Nucleus
ONM
outer nuclear membrane
Microfilament Proteins
INM
inner nuclear membrane
Membrane Proteins
Nuclear Proteins
Reproducibility of Results
IP
immunoprecipitation
Cell-cell junctions
EDMD
Emery–Dreifuss muscular dystrophy
IF
immunofluorescence microscopy
Protein Transport
F-actin
filamentous actin
Intercellular Junctions
WB
Western blot
NE
nuclear envelope
Nesprin-2
Β-catenin
SR
spectrin repeat
LINC
Linker of nucleoskeleton and cytoskeleton
Protein Binding
Signal Transduction
Research Article
Zdroj: Experimental Cell Research
ISSN: 1090-2422
Popis: The spatial compartmentalisation of biochemical signalling pathways is essential for cell function. Nesprins are a multi-isomeric family of proteins that have emerged as signalling scaffolds, herein, we investigate the localisation and function of novel nesprin-2 N-terminal variants. We show that these nesprin-2 variants display cell specific distribution and reside in both the cytoplasm and nucleus. Immunofluorescence microscopy revealed that nesprin-2 N-terminal variants colocalised with β-catenin at cell-cell junctions in U2OS cells. Calcium switch assays demonstrated that nesprin-2 and β-catenin are lost from cell-cell junctions in low calcium conditions whereas emerin localisation at the NE remained unaltered, furthermore, an N-terminal fragment of nesprin-2 was sufficient for cell-cell junction localisation and interacted with β-catenin. Disruption of these N-terminal nesprin-2 variants, using siRNA depletion resulted in loss of β-catenin from cell-cell junctions, nuclear accumulation of active β-catenin and augmented β-catenin transcriptional activity. Importantly, we show that U2OS cells lack nesprin-2 giant, suggesting that the N-terminal nesprin-2 variants regulate β-catenin signalling independently of the NE. Together, these data identify N-terminal nesprin-2 variants as novel regulators of β-catenin signalling that tether β-catenin to cell-cell contacts to inhibit β-catenin transcriptional activity.
Highlights • N-terminal nesprin-2 variants display cell specific expression patterns. • N-terminal spectrin repeats of nesprin-2 interact with β-catenin. • N-terminal nesprin-2 variants scaffold β-catenin at cell-cell junctions.. • Nesprin-2 variants play multiple roles in β-catenin signalling.
Databáze: OpenAIRE
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