Cyclin H is a regulatory subunit of the cyclin-dependent kinase (CDK)-activating kinase (CAK) complex, which primarily associates with CDK7 and MAT1. This ternary complex plays dual roles in cell cycle regulation and transcription. In the cell cycle, Cyclin H/CDK7 phosphorylates and activates CDKs (e.g., CDK1. CDK2. CDK4. CDK6) that drive progression through the G1/S and G2/M phases. In transcription, the complex functions as a component of the general transcription factor TFIIH, facilitating RNA polymerase II-mediated gene expression by phosphorylating its C-terminal domain. Dysregulation of Cyclin H expression or activity has been linked to cancer, neurodegenerative disorders, and developmental defects, making it a subject of interest in both basic and clinical research.
Antibodies targeting Cyclin H are essential tools for studying its expression, localization, and interactions. They are widely used in techniques like Western blotting, immunofluorescence, immunoprecipitation, and immunohistochemistry to investigate Cyclin H's roles in cell cycle checkpoints, transcriptional regulation, and DNA repair mechanisms. Such antibodies also aid in exploring Cyclin H's potential as a therapeutic target, particularly in cancers where CDK7 inhibition is being evaluated. Validation of Cyclin H antibodies typically involves testing specificity using knockout cell lines or siRNA-mediated knockdown. Given its conserved function across eukaryotes, these antibodies have applications in diverse model organisms, further supporting their utility in mechanistic and translational studies.