Defective signaling, osteoblastogenesis and bone remodeling in a mouse model of connexin 43 C-terminal truncation.
Megan C MoorerCarla HebertRyan E TomlinsonShama R IyerMax ChasonJoseph P StainsPublished in: Journal of cell science (2017)
In skeletal tissue, loss or mutation of the gap junction protein connexin 43 (Cx43, also known as GJA1) in cells of the osteoblast lineage leads to a profound cortical bone phenotype and defective tissue remodeling. There is mounting evidence in bone cells that the C-terminus (CT) of Cx43 is a docking platform for signaling effectors and is required for efficient downstream signaling. Here, we examined this function, using a mouse model of Cx43 CT-truncation (Gja1 K258Stop). Relative to Gja1+/- controls, male Gja1-/K258Stop mice have a cortical bone phenotype that is remarkably similar to those reported for deletion of the entire Cx43 gene in osteoblasts. Furthermore, we show that the Cx43 CT binds several signaling proteins that are required for optimal osteoblast function, including PKCδ, ERK1 and ERK2 (ERK1/2, also known as MAPK3 and MAPK1, respectively) and β-catenin. Deletion of the Cx43 CT domain affects these signaling cascades, impacting osteoblast proliferation, differentiation, and collagen processing and organization. These data imply that, at least in bone, Cx43 gap junctions not only exchange signals, but also recruit the appropriate effector molecules to the Cx43 CT in order to efficiently activate signaling cascades that affect cell function and bone acquisition.
Keyphrases
- signaling pathway
- bone regeneration
- bone mineral density
- computed tomography
- mouse model
- image quality
- induced apoptosis
- dual energy
- contrast enhanced
- soft tissue
- bone loss
- oxidative stress
- positron emission tomography
- magnetic resonance imaging
- epithelial mesenchymal transition
- gene expression
- magnetic resonance
- cell cycle arrest
- machine learning
- high throughput
- molecular dynamics
- metabolic syndrome
- single molecule
- autism spectrum disorder
- dna methylation
- transcription factor
- molecular dynamics simulations
- dendritic cells
- cell death
- deep learning
- wound healing