Loss of Kat2b impairs intraflagellar transport and the Hedgehog signaling pathway in primary cilia.

Primary cilia are sensory organelles that regulate various signaling pathways. When microtubules are compared to a highway, motor proteins carry and transport cargo proteins, which are tuned by post-translational modifications, such as acetylation. However, the role of acetylation in primary cilia regulation remains unclear. In this study, histone K (lysine) acetyltransferase 2 B (Kat2b) was identified as a novel regulator of primary cilia. Kat2b, which mainly regulates transcription as a p300/CBP associated factor, is localized to the cytosol, centrosome, and cilium basal body. In addition, basal Kat2b expression gradually increased during ciliogenesis. Kat2b regulates the rate of cilia assembly, particularly in the early stages, and loss of Kat2b reduces the recruitment of intraflagellar transport (IFT) components to the ciliary axoneme and impairs Hedgehog (Hh) signaling activation. In addition, Kat2b-knockout mice showed mild abnormalities and ciliary IFT defects in the kidneys. These results establish a link between acetylation regulated by Kat2b and its relevance to ciliary assembly and function.