Domain-to-domain coupling in voltage-sensing phosphatase

Area of Science:

• Biophysics
• Molecular Biology
• Cell Physiology

Background:

• Voltage-sensing phosphatase (VSP) comprises a transmembrane voltage sensor and a cytoplasmic enzyme region.
• The enzyme region, similar to PTEN, dephosphorylates phosphoinositides, with activity triggered by membrane depolarization.
• The coupling mechanism between VSP's voltage sensor and enzyme regions remains poorly understood.

Purpose of the Study:

• To investigate the coupling mechanism between the voltage sensor domain and the enzyme region in VSP.
• To determine if this coupling mechanism is conserved in other voltage sensor domain-containing proteins.
• To elucidate how membrane potential changes regulate VSP's enzymatic activity.

Main Methods:

• Utilizing fluorescent unnatural amino acid incorporation for genetic labeling of specific amino acid sites.
• Detecting local structural changes within the cytoplasmic region of *Ciona intestinalis* VSP.
• Correlating structural dynamics with changes in membrane potential.

Main Results:

• Local structural changes in the cytoplasmic region of VSP were detected upon alterations in membrane potential.
• These observed structural dynamics provide insights into the regulation of VSP's enzymatic activity by its voltage sensor.
• The study offers a novel perspective on the voltage-dependent activation of VSP.

Conclusions:

• The voltage sensor domain directly influences the cytoplasmic enzyme region of VSP through specific structural rearrangements.
• Understanding this coupling mechanism is crucial for comprehending VSP function and its regulation.
• This research contributes to the broader understanding of voltage-gated protein regulation.