Karolina Pavic, Nikhil Gupta, Judit Domènech Omella, Rita Derua, Anna Aakula, Riikka Huhtaniemi, Juha A Määttä, Nico Höfflin, Juha Okkeri, Zhizhi Wang, Otto Kauko, Roosa Varjus, Henrik Honkanen, Daniel Abankwa, Maja Köhn, Vesa P Hytönen, Wenqing Xu, Jakob Nilsson, Rebecca Page, Veerle Janssens, Alexander Leitner, Jukka Westermarck
The protein phosphatase 2A (PP2A) heterotrimer PP2A-B56α is a human tumour suppressor. However, the molecular mechanisms inhibiting PP2A-B56α in cancer are poorly understood. Here, we report molecular level details and structural mechanisms of PP2A-B56α inhibition by an oncoprotein CIP2A. Upon direct binding to PP2A-B56α trimer, CIP2A displaces the PP2A-A subunit and thereby hijacks both the B56α, and the catalytic PP2Ac subunit to form a CIP2A-B56α-PP2Ac pseudotrimer. Further, CIP2A competes with B56α substrate binding by blocking the LxxIxE-motif substrate binding pocket on B56α...
February 28, 2023: Nature Communications