High-resolution cryo-EM of a small protein complex: The structure of the human CDK-activating kinase

Area of Science:

• Structural Biology
• Molecular Biology
• Biochemistry

Background:

• The human CDK-activating kinase (CAK) is a crucial regulator of cell cycle progression and transcription initiation.
• CAK's critical roles make it a significant target for cancer drug discovery programs.
• Previous limitations in structural determination hindered understanding of CAK's regulation and interactions.

Purpose of the Study:

• To review the progress in determining the structure of the active human CAK complex.
• To highlight how recent technological advancements in cryo-EM have overcome previous structural barriers.
• To provide insights into the regulation and cellular interactions of human CAK.

Main Methods:

• Utilized cryogenic electron microscopy (cryo-EM) for structure determination.
• Leveraged advanced cryo-EM technologies following the 'resolution revolution'.
• Achieved near-atomic resolution maps, routinely at 2Å or better.

Main Results:

• Successfully obtained high-resolution structures of the intact human CAK complex.
• Demonstrated the capability of modern cryo-EM to resolve small, previously intractable protein complexes.
• Provided unprecedented structural insights into human CAK.

Conclusions:

• Recent cryo-EM advancements have enabled high-resolution structural determination of human CAK.
• These structures offer critical insights into CAK regulation, substrate interactions, and inhibitor binding.
• The findings pave the way for improved cancer drug discovery targeting CAK.