N-α-acetyltransferase 10 protein is a negative regulator of 28S proteasome through interaction with PA28β

N-alpha-acetyltransferase 10 protein (Naa10p) regulates various pathways associated with cancer cell proliferation, metastasis, apoptosis and autophagy. However, its role in protein quality control is unknown. Here, we report that Naa10p is physically associated with proteasome activator 28 beta (PA28 beta). Naa10p also interacts with PA28 alpha in a PA28 beta-dependent manner. Naa10p negatively regulates PA28-dependent chymotrypsin-like proteasome activity in cancer cells and in a cell-free system reconstituted with purified proteins, which is not related to 26S proteasome. Acetyltransferase activity of Naa10p is not required for its effect on chymotrypsin-like proteasome activity. Therefore, our data reveal that Naa10p suppresses 28S proteasome activity through interaction with PA28 beta. Structured summary of protein interactions: Naa10p physically interacts with PA28 alpha and PA28 beta by anti bait coimmunoprecipitation (View Interaction: 1, 2) (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.