Potassium Channel Tetramerisation Domain Containing Protein 5 (KCTD5)

KCTD5, encoding a deduced 234-amino acid protein that interacts with the large regulatory proteins Rep78 and Rep68 of adeno-associated virus-2 (AAV-2). KCTD5 contains an N-terminal voltage-gated potassium channel tetramerization domain (T1). The Rep68 and Rep78 proteins are essential for AAV-2 DNA replication and regulation of AAV expression when helper virus is present.

In the absence of Rep protein expression, KCTD5 was located almost exclusively in the cytoplasm; upon expression of Rep78 or Rep68, KCTD5 was found predominantly in the nucleus. KCTD5 overexpression completely abrogated Rep68-mediated posttranscriptional activation of an HIV-LTR-driven luciferase reporter gene.