Potassium channel tetramerization domain-containing protein 4 (KCTD4)

Potassium channel tetramerization domain-containing protein 4 (KCTD4) is a mammalian protein containing a BTB (Broad-Complex, Tramtrack and Bric-a-brac)/POZ (POxvirus and Zinc finger) domain, which facilitates protein–protein interactions and often acts as an adaptor in Cullin 3-containing ubiquitin ligase complexes. Although named for its homology to potassium channel tetramerization domains, KCTD4 does not itself function as a potassium channel, but instead regulates cellular processes via its interaction partners. KCTD4 is strongly implicated in cancer metastasis, especially in esophageal squamous cell carcinoma, where it interacts with CLIC1 to disturb calcium homeostasis and activate NFATc1-dependent gene expression essential for metastatic behavior. KCTD4 is proposed as both a therapeutic target and biomarker for cancer metastasis, with experimental inhibitors under investigation. Broader roles likely include regulation of protein degradation and transcription, in common with other KCTD family members.

Other names

BTB/POZ domain-containing protein KCTD4potassium channel tetramerisation domain containing 4bA321C24.3

Inhibition of KCTD4–CLIC1 interaction disrupts downstream Ca²⁺ signaling, blocks NFATc1-dependent fibronectin transcription, and suppresses cancer metastasis