Download MendeleyRPTP alpha phosphatase activity is allosterically regulated by the membrane-distal catalytic domain.
Wen, Y., Yang, S., Wakabayashi, K., Svensson, M.N.D., Stanford, S.M., Santelli, E., Bottini, N.(2020) J Biol Chem 295: 4923-4936
- PubMed: 32139509
- DOI: https://doi.org/10.1074/jbc.RA119.011808
- Primary Citation of Related Structures:
6UZT - PubMed Abstract:
Receptor-type protein tyrosine phosphatase α (RPTPα) is an important positive regulator of SRC kinase activation and a known promoter of cancer growth, fibrosis, and arthritis. The domain structure of RPTPs comprises an extracellular region, a transmembrane helix, and two tandem intracellular catalytic domains referred to as D1 and D2. The D2 domain of RPTPs is believed to mostly play a regulatory function; however, no regulatory model has been established for RPTPα-D2 or other RPTP-D2 domains. Here, we solved the 1.8 Å resolution crystal structure of the cytoplasmic region of RPTPα, encompassing D1 and D2, trapped in a conformation that revealed a possible mechanism through which D2 can allosterically inhibit D1 activity. Using a D2-truncation RPTPα variant and mutational analysis of the D1/D2 interfaces, we show that D2 inhibits RPTPα phosphatase activity and identified a 405 PFTP 408 motif in D1 that mediates the inhibitory effect of D2. Expression of the gain-of-function F406A/T407A RPTPα variant in HEK293T cells enhanced SRC activation, supporting the relevance of our proposed D2-mediated regulation mechanism in cell signaling. There is emerging interest in the development of allosteric inhibitors of RPTPs but a scarcity of validated allosteric sites for RPTPs. The results of our study not only shed light on the regulatory role of RPTP-D2 domains, but also provide a potentially useful tool for the discovery of chemical probes targeting RPTPα and other RPTPs.
Organizational Affiliation:
Department of Medicine, University of California, San Diego, La Jolla, California 92037.
