CDK7 Protein, Human (sf9, GST)

CDK7, in conjunction with its regulatory partners CCNH and MNAT1, functions as a serine/threonine kinase with pivotal roles in cell cycle regulation and RNA polymerase II-mediated transcription. As a catalytic subunit of the CDK-activating kinase (CAK) complex, CDK7 plays a critical role in the activation and formation of CDK1/cyclin-B during the G2-M transition and CDK2/cyclins during the G1-S transition. Its phosphorylation targets include SPT5/SUPT5H, SF1/NR5A1, POLR2A, p53/TP53, CDK1, CDK2, CDK4, CDK6, and CDK11B/CDK11. Through threonine phosphorylation, CAK activates cyclin-associated kinases, thereby regulating cell cycle progression. Moreover, CDK7, when complexed with the core-TFIIH basal transcription factor, facilitates RNA polymerase II activation by serine phosphorylation of the C-terminal domain (CTD) of its large subunit (POLR2A). This activation enables RNA polymerase II to escape the promoter and initiate transcript elongation. CDK7's consistent expression and activity throughout the cell cycle contribute to its involvement in DNA-bound peptides-mediated transcription and cellular growth inhibition. Additionally, in response to DNA damage, CDK7 triggers the activation of p53/TP53, forming a feedback loop where p53/TP53 can subsequently inactivate CDK7, potentially leading to cell cycle arrest, transcriptional shutdown, and cellular recovery or apoptosis.