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

• Naa10p directly interacts with proteasome activator 28β (PA28β).
• Naa10p interacts with PA28α in a PA28β-dependent manner.
• Naa10p inhibits PA28-dependent chymotrypsin-like proteasome activity.
• Naa10p regulates 28S proteasome activity independent of acetylation.

N-α-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 28β (PA28β). Naa10p also interacts with PA28α in a PA28β-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 PA28β.Structured summary of protein interactionsNaa10pphysically interacts with PA28 alpha and PA28 beta by anti bait coimmunoprecipitation (View Interaction: 1, 2)