Cryo-EM structures of apo and antagonist-bound human Ca_v3.1

Area of Science:

• Structural Biology
• Neuroscience
• Pharmacology

Background:

• T-type calcium channels (Ca_v3.1-Ca_v3.3) are crucial low-voltage-activated channels.
• Abnormal T-type channel activity is linked to epilepsy, psychiatric disorders, and pain.
• Understanding T-type channel structure is vital for developing targeted therapeutics.

Purpose of the Study:

• To elucidate the structural basis of human Ca_v3.1 channel function.
• To determine the structure of Ca_v3.1 in complex with the selective blocker Z944.
• To provide a structural framework for understanding T-type calcium channel subtypes.

Main Methods:

• Cryo-electron microscopy (cryo-EM) was employed to resolve structures.
• High-resolution structures were obtained for human Ca_v3.1 alone and with Z944.
• Structural analysis focused on the pore domain and blocker interaction site.

Main Results:

• The cryo-EM structure of human Ca_v3.1 was determined at 3.3 Å resolution.
• The structure of Ca_v3.1 complexed with Z944 was resolved at 3.1 Å resolution.
• Z944 binds within the central cavity, interacting with the pore domain and blocking ion flow.

Conclusions:

• The determined structures offer unprecedented atomic detail of human T-type calcium channels.
• The findings reveal the precise binding mode of the selective blocker Z944.
• These structures serve as a foundation for comparative studies of Ca_v subfamily properties and drug development.