TRPM5 Channel Binds Calcium-Binding Proteins Calmodulin and S100A1

Area of Science:

• Molecular biology
• Biophysics
• Neuroscience

Background:

• Transient Receptor Potential Melastatin 5 (TRPM5) channels are crucial for calcium-mediated taste transduction.
• TRP channels are modulated by intracellular and extracellular agents binding to their termini.
• Intracellular termini can exhibit intrinsically disordered protein (IDP) characteristics, enabling diverse molecular interactions.

Purpose of the Study:

• To investigate the intracellular N-termini of the TRPM5 channel.
• To identify calcium-binding proteins (CBPs) that interact with TRPM5.
• To characterize the binding interface and molecular interactions between TRPM5 and identified CBPs.

Main Methods:

• In vitro binding assays were employed to detect interactions between TRPM5 N-termini and CBPs.
• Molecular docking simulations were used to predict binding modes.
• Molecular dynamics simulations (MDs) were performed to analyze the stability and dynamics of the complexes.

Main Results:

• The study identified calmodulin (CaM) and S100A1 as intracellular binding partners for the TRPM5 N-termini.
• In vitro assays confirmed the binding of CaM and S100A1 to TRPM5.
• Molecular simulations validated known binding interface patterns and highlighted unique basic residues in TRPM5's binding regions for CaM/S100A1.

Conclusions:

• The N-termini of TRPM5 directly interact with key calcium-binding proteins, CaM and S100A1.
• These interactions involve specific binding interfaces and unique residue characteristics.
• This finding provides insights into the molecular mechanisms of TRPM5 regulation and calcium signaling in taste transduction.