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Striatal‐enriched protein tyrosine phosphatase regulates the PTP α/Fyn signaling pathway
Author(s) -
Xu Jian,
Kurup Pradeep,
Foscue Ethan,
Lombroso Paul J.
Publication year - 2015
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/jnc.13160
Subject(s) - fyn , protein tyrosine phosphatase , microbiology and biotechnology , dephosphorylation , phosphorylation , biology , proto oncogene tyrosine protein kinase src , tyrosine , tyrosine phosphorylation , phosphatase , src family kinase , signal transduction , chemistry , biochemistry
The tyrosine kinase Fyn has two regulatory tyrosine residues that when phosphorylated either activate (Tyr 420 ) or inhibit (Tyr 531 ) Fyn activity. Within the central nervous system, two protein tyrosine phosphatases ( PTP s) target these regulatory tyrosines in Fyn. PTP α dephosphorylates Tyr 531 and activates Fyn, while STEP (STriatal‐Enriched protein tyrosine Phosphatase) dephosphorylates Tyr 420 and inactivates Fyn. Thus, PTP α and STEP have opposing functions in the regulation of Fyn; however, whether there is cross talk between these two PTP s remains unclear. Here, we used molecular techniques in primary neuronal cultures and in vivo to demonstrate that STEP negatively regulates PTP α by directly dephosphorylating PTP α at its regulatory Tyr 789 . Dephosphorylation of Tyr 789 prevents the translocation of PTP α to synaptic membranes, blocking its ability to interact with and activate Fyn. Genetic or pharmacologic reduction in STEP 61 activity increased the phosphorylation of PTP α at Tyr 789 , as well as increased translocation of PTP α to synaptic membranes. Activation of PTP α and Fyn and trafficking of GluN2B to synaptic membranes are necessary for ethanol (EtOH) intake behaviors in rodents. We tested the functional significance of STEP 61 in this signaling pathway by EtOH administration to primary cultures as well as in vivo , and demonstrated that the inactivation of STEP 61 by EtOH leads to the activation of PTP α, its translocation to synaptic membranes, and the activation of Fyn. These findings indicate a novel mechanism by which STEP 61 regulates PTP α and suggest that STEP and PTP α coordinate the regulation of Fyn.STEP 61 , PTPα, Fyn, and NMDA receptor (NMDAR) have been implicated in ethanol intake behaviors in the dorsomedial striatum (DMS) in rodents. Here, we report that PTPα is a novel substrate for STEP 61 . Upon ethanol exposure, STEP 61 is phosphorylated and inactivated by protein kinase A (PKA) signaling in the DMS. As a result of STEP 61 inhibition, there is an increase in the phosphorylation of PTPα, which translocates to lipid rafts and activates Fyn and subsequent NMDAR signaling. The results demonstrate a synergistic regulation of Fyn‐NMDAR signaling by STEP 61 and PTPα, which may contribute to the regulation of ethanol‐related behaviors. NMDA, N ‐methyl‐ d ‐aspartate; PTPα, receptor‐type protein tyrosine phosphatase alpha; STEP, STriatal‐Enriched protein tyrosine Phosphatase.