Protein⁻Protein Interactions with Connexin 43: Regulation and Function.

Area of Science:

• Cellular Biology
• Biochemistry
• Cardiovascular Physiology

Background:

• Connexins are integral membrane proteins forming gap junctions, essential for direct intercellular communication of ions and metabolites.
• In cardiac tissue, gap junctions, primarily formed by connexin 43 (Cx43), are critical for action potential propagation and maintaining heart rhythm.
• Numerous proteins interact with connexins, modulating gap junction function by promoting or inhibiting cell coupling.

Purpose of the Study:

• To review the functional and regulatory roles of proteins interacting with connexin 43 (Cx43).
• To consolidate current knowledge on Cx43 interacting proteins and their impact on gap junction regulation.
• To highlight the significance of these interactions at the intercalated disc, a key site of Cx43 regulation.

Main Methods:

• Literature review summarizing existing research on connexin-interacting proteins.
• Analysis of studies employing immunohistochemistry for co-localization and biophysical methods for direct interaction confirmation.
• Focus on interactions specifically involving connexin 43 (Cx43).

Main Results:

• Connexin interacting proteins influence gap junction coupling by affecting channel trafficking, opening, closure, internalization, and degradation.
• Interactions can be direct (e.g., kinase activity) or indirect through complex formation (e.g., with cytoskeleton proteins).
• Cx43 interactions are extensively studied, with significant regulatory roles identified at the cardiac intercalated disc.

Conclusions:

• Protein interactions are crucial for the precise regulation of connexin 43 (Cx43) function in the heart.
• Understanding these interactions provides insights into cardiac electrophysiology and potential therapeutic targets.
• The intercalated disc serves as a critical nexus for Cx43 regulation and function, influenced by its interacting partners.