An arrestin-1 surface opposite of its interface with photoactivated rhodopsin engages with enolase-1

Area of Science:

• Molecular and Cellular Biology
• Biochemistry
• Signal Transduction

Background:

• Arrestin-1 (also known as arrestin/cone arrestin) is crucial for rhodopsin inactivation in photoreceptors.
• Beyond phototransduction, arrestin-1 interacts with various partners, influencing diverse cellular signaling pathways.
• Enolase-1 is a key enzyme in glycolysis, but its interactions with arrestin-1 are not well understood.

Purpose of the Study:

• To map the molecular interaction sites between arrestin-1 and enolase-1.
• To investigate how arrestin-1 binding impacts the catalytic activity of enolase-1.
• To elucidate the structural basis for arrestin-1's modulation of enolase-1 activity.

Main Methods:

• Fluorescence quench protection assays were used to identify arrestin-1 surface regions interacting with enolase-1.
• A molecular model of the arrestin-1-enolase-1 complex was constructed and validated using charge-pair interaction substitutions.
• Site-directed mutagenesis of arrestin-1 was performed to assess the impact on enolase-1 binding and catalytic activity.

Main Results:

• Arrestin-1 binds enolase-1 at a surface distinct from its rhodopsin-binding site.
• A validated molecular model details the arrestin-1-enolase-1 complex structure.
• Selective mutations in arrestin-1 eliminated its effect on enolase-1 catalysis without disrupting binding.

Conclusions:

• Arrestin-1 interacts with enolase-1 at a novel interface, modulating its enzymatic function.
• The findings provide a structural basis for understanding arrestin-1's non-visual signaling roles.
• This study opens avenues for exploring arrestin-1's influence on enolase-1 activity in various cellular contexts.