Regulation of receptor protein-tyrosine phosphatase alpha by oxidative stress.
The presence of two protein-tyrosine phosphatase (PTP) domains is a striking feature in most transmembrane receptor PTPs (RPTPs). The function of the generally inactive membrane-distal PTP domain (RPTP-D2) is unknown. Here we report that an intramolecular interaction between the spacer region (Sp) and the C-terminus in RPTPalpha prohibited intermolecular interactions. Interestingly, stress factors such as H(2)O(2), UV and heat shock induced reversible, free radical-dependent, intermolecular interactions between RPTPalpha and RPTPalpha-SpD2, suggesting an inducible switch in conformation and binding. The catalytic site cysteine of RPTPalpha-SpD2, Cys723, was required for the H(2)O(2) effect on RPTPalpha. H(2)O(2) induced a rapid, reversible, Cys723-dependent conformational change in vivo, as detected by fluorescence resonance energy transfer, with cyan fluorescent protein (CFP) and yellow fluorescent protein (YFP) flanking RPTPalpha-SpD2 in a single chimeric protein. Importantly, H(2)O(2) treatment stabilized RPTPalpha dimers, resulting in inactivation. We propose a model in which oxidative stress induces a conformational change in RPTPalpha-D2, leading to stabilization of RPTPalpha dimers, and thus to inhibition of RPTPalpha activity.
Blanchetot
Christophe
C
Hubrecht Laboratory, Netherlands Institute for Developmental Biology, Uppsalalaan 8, NL-3584 CT Utrecht, The Netherlands.
Tertoolen
Leon G J
LG
den Hertog
Jeroen
J
D020134:Catalytic Domain; D002460:Cell Line; D019281:Dimerization; D004735:Energy Transfer; D005453:Fluorescence; D006358:Hot Temperature; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D008164:Luminescent Proteins / Q000235:genetics; D018384:Oxidative Stress; D011487:Protein Conformation; D017027:Protein Tyrosine Phosphatases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D011956:Receptors, Cell Surface / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000378:metabolism*; D014466:Ultraviolet Rays
D008164:Luminescent Proteins; D011956:Receptors, Cell Surface; D006861:Hydrogen Peroxide; D017027:Protein Tyrosine Phosphatases