Related Experiment Video
Updated: Jul 13, 2026
10:46
Mechanical Stimulation-induced Calcium Wave Propagation in Cell Monolayers: The Example of Bovine Corneal Endothelial Cells
Published on: July 16, 2013
Key connexin 43 phosphorylation events regulate the gap junction life cycle
1Fred Hutchinson Cancer Research Center, Seattle, WA 98109, USA.
The Journal of Membrane Biology
|July 17, 2007
Summary
Connexin 43 (Cx43) phosphorylation at specific sites regulates its trafficking and gap junction formation. This study uses phosphospecific antibodies to map Cx43 phosphorylation events, clarifying signaling pathways.
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- Connexin 43 (Cx43) is a key vertebrate gap junction protein.
- Cx43 undergoes phosphorylation during its synthesis, trafficking, and assembly into gap junctions.
- Electrophoretic mobility shifts (P0, P1, P2) are commonly used to infer Cx43 phosphorylation status.
Purpose of the Study:
- To utilize phosphospecific and epitope-specific antibodies to precisely map Cx43 phosphorylation events.
- To identify specific serine residues involved in Cx43 isoform transitions (P1, P2).
- To elucidate signaling pathways regulating Cx43 function through defined phosphorylation events.
Main Methods:
- Employing phosphospecific and epitope-specific antibodies against Connexin 43 (Cx43).
- Analyzing Cx43 phosphorylation sites (S364, S365, S325, S328, S330, S368, S279/S282, S262).
- Investigating Cx43 mobility shifts in response to protein kinase C activators and mitogen-activated protein kinase activity in CHO and MDCK cells.
Main Results:
- Phosphorylation at S364/S365 is linked to the P1 Cx43 isoform, potentially regulating plasma membrane trafficking.
- Phosphorylation at S325/S328/S330 is essential for the P2 Cx43 isoform, found exclusively in gap junctions.
- Protein kinase C activation induces Cx43 phosphorylation at S368, S279/S282, and S262, causing mobility shifts dependent on MAPK activity, with S262 phosphorylation potentially explaining the shift.
Conclusions:
- Specific Cx43 phosphorylation events at distinct serine residues (S364/S365, S325/S328/S330) define different Cx43 isoforms (P1, P2).
- These phosphorylation events play critical roles in Cx43 trafficking, gap junction formation, and overall gap junction function.
- The study provides a framework for understanding the signaling pathways that modulate Cx43 activity through site-specific phosphorylation.
Related Concept Videos
01:37Gap Junctions
Multicellular organisms employ a variety of ways for cells to communicate with each other. Gap junctions are specialized proteins that form pores between neighboring cells in animals, connecting the cytoplasm between the two, and allowing for the exchange of molecules and ions. They are found in a wide range of invertebrate and vertebrate species, mediate numerous functions including cell differentiation and development, and are associated with numerous human diseases, including cardiac and...
01:27Gap Junctions
The cytoplasm of adjacent animal cells can exchange small molecules, ions, and secondary messengers via the communication channels which form the gap junctions. These junctions comprise a few hundred to thousands of molecular channels, each made of two halves, called the connexon hemichannel. A connexon is a hexamer of six transmembrane connexin proteins, which assemble radially, thus forming a pore or channel in the center. One connexon hemichannel docks with a corresponding connexon on the...
01:19Contact-dependent Signaling
Contact-dependent signaling, as the name suggests, requires that communicating cells be in direct contact with each other. This is achieved either through receptor-ligand interactions or by specialized cytoplasmic channels that allow the flow of small molecules between cells. In animal cells, channels called gap junctions facilitate contact-dependent signaling in certain tissues, whereas, plasmodesmata perform a similar function in plants.
Gap Junctions
In animal cells, gap junctions are formed...
Gap Junctions
In animal cells, gap junctions are formed...
01:14Overview of Cell-Cell Junctions
The complex three-dimensional arrangement of cells in any multicellular organism is defined and maintained by interactions of cells with each other and the extracellular matrix. Cell-cell junctions are specialized structures where the multi-protein complexes on one cell interact with the multi-protein complexes on another cell. These cell junctions are classified into three main types based on their function — occluding, anchoring, and gap junctions.
Occluding or Tight Junctions
Tight...
Occluding or Tight Junctions
Tight...
01:22Amplifying Signals via Enzymatic Cascade
When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze the...
01:30Ligand-Gated Ion Channel Receptor: Gating Mechanism
Ligand-gated ion channels are transmembrane proteins that play a vital role in intercellular communication and functions of the nervous system. They allow the influx of ions across the membrane once the neurotransmitter binds, allowing the subsequent transmission of electrical excitation across the neurons. Other ligand-gated ion channels, like the γ-aminobutyric acid (GABA) receptor, permit anions like chloride into the cells on the binding of the GABA molecule. Their entry into the cell...