Poster Presentation 11th International Symposium on Autophagy 2025

ZPR9 interacts with ULK1 to regulate autophagy in liver cell. (#242)

JUNGKEUN OH 1 , MINKYUNG CHO 1 , HYUNA Seong 1
  1. Chungbuk national university, Cheongju-si, CHUNGCHEONGBUK-DO, South Korea

Autophagy is a fundamental cellular catabolic process that degrades dysfunctional organelles and proteins to maintain homeostasis, especially in response to metabolic stress. Impaired autophagy is known as a key pathological feature of Fatty Liver Disease, highlighting its importance for hepatic function. ULK1 (Unc-51 like autophagy activating kinase 1) is a serine/threonine kinase that acts as a critical initiator of the autophagy pathway. Zinc finger protein ZPR9, on the other hand, is a protein that is known as substrate of MPK38/MELK, a serine threonine kinase of AMPK family. However the exact function of this protein is not well-defined. This study investigates the potential interaction between ZPR9 and ULK1 and its impact on autophagy regulation in a cellular model of Fatty liver. At the cellular level, the direct interaction between ZPR9 and ULK1 was identified at the endogenous and exogenous level. In addition, immunofluorescence (IF) experiments confirmed the co-localization of ZPR9 and ULK1 in the cell. Furthermore, the expression of ULK1 and autophagy related proteins were elevated under ZPR9 overexpression, which was further enhanced by OA. These findings identify ZPR9 as a novel ULK1-interacting protein that is regulated by metabolic stress, suggesting that the ZPR9-ULK1 axis could be a potential therapeutic target for liver diseases associated with dysfunctional autophagy.

  1. Seong, H. A., Manoharan, R., & Ha, H. (2012). Zinc finger protein ZPR9 functions as an activator of AMPK-related serine/threonine kinase MPK38/MELK involved in ASK1/TGF-β/p53 signaling pathways. BMB Reports, 45(10), 584–589.
  2. Wang, C., Wang, H., Zhang, D., Luo, W., Liu, R., Xu, D., Diao, L., Liao, L., & Liu, Z. (2018). Phosphorylation of ULK1 affects autophagosome fusion and links chaperone-mediated autophagy to macroautophagy. Nature Communications, 9, 3492.