Abstract
The N-acetyltransferase arrest defective 1 (ARD1) is an important regulator of cell growth and differentiation that has emerged recently as a critical molecule in cancer progression. However, the regulation of the enzymatic and biological activities of human ARD1 (hARD1) in cancer is presently poorly understood. Here, we report that hARD1 undergoes autoacetylation and that this modification is essential for its functional activation. Using liquid chromatography-tandem mass spectrometry and site-directed mutational analyses, we identified K136 residue as an autoacetylation target site. K136R mutation abolished the ability of hARD1 to promote cancer cell growth in vitro and tumor xenograft growth in vivo. Mechanistic investigations revealed that hARD1 autoacetylation stimulated cyclin D1 expression through activation of the transcription factors beta-catenin and activator protein-1. Our results show that hARD1 autoacetylation is critical for its activation and its ability to stimulate cancer cell proliferation and tumorigenesis.
Highlights
Posttranslational modification is a pivotal regulatory molecular switch of cell signaling pathways and gene expression
Results human ARD1 (hARD1) is acetylated by itself Recombinant hARD1 was acetylated by incubation with acetyl-CoA in a time-dependent manner, whereas autoacetylation disappeared on denaturation of hARD1 by 0.1% SDS or when acetyl-CoA was absent (Fig. 1A, left)
K136R and R82A/Y122F mutants did not significantly influence extracellular signal-regulated kinase 1/2 (ERK1/2) activation (Supplementary Fig. S4D). These results suggest that autoacetylation of hARD1 is required for activator protein-1 (AP-1) activation mediated by ERK1/2
Summary
Posttranslational modification is a pivotal regulatory molecular switch of cell signaling pathways and gene expression. A number of kinases can be activated by an autoregulatory system called autophosphorylation [1, 2]. Autophosphorylation, acetyltransferases acetylate themselves for its catalytic and functional activities [4,5,6,7,8,9]. Arrest defective 1 (ARD1) was originally identified to catalyze NH2-terminal α-acetylation in yeast [10]. Several studies revealed that mammalian ARD1 catalyzes ε-lysine acetylation of hypoxia-inducible factor-1α, β-catenin, myosin light chain kinase, and tubulin fractions [11,12,13,14,15,16,17]. Knockdown of human ARD1 (hARD1) inhibits cellular growth and induces G1 arrest [12, 13, 18]. ARD1 is increasingly recognized as an important molecule involved in cancer progression, but the regulation of its biological activity remains largely unknown
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
