The proteasome regulates the interaction between Cx43 and ZO-1

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Gap junction (GJ) intercellular communication (GJIC) is crucial for cell and tissue function.
• Connexins form GJ, and their stability/distribution impacts GJIC.
• The proteasome's role in Cx43 internalization and GJIC regulation is not fully understood.

Purpose of the Study:

• To investigate the proteasome's role in regulating connexin 43 (Cx43) internalization.
• To elucidate the molecular mechanisms by which the proteasome influences Cx43 internalization and GJIC.
• To explore the interaction between Cx43 and ZO-1 in proteasome-mediated regulation.

Main Methods:

• Immunoprecipitation experiments with proteasome inhibitors.
• Immunofluorescence analysis.
• Overexpression of ZO-1 PDZ2 domain and V5/HIS-tagged Cx43.

Main Results:

• Proteasome inhibition alters the interaction between Cx43 and ZO-1.
• The PDZ2 domain of ZO-1 and the C-terminus of Cx43 are involved in their interaction.
• Reduced Cx43-ZO-1 interaction leads to Cx43 accumulation and formation of large GJ plaques at the plasma membrane.

Conclusions:

• The proteasome regulates GJIC by modulating Cx43 and ZO-1 interaction.
• This pathway suggests how proteasome dysfunction can affect GJIC and cell communication.
• Alterations in proteasome activity may contribute to cell and tissue dysfunction.