Shp‐2 Specifically Regulates Several Tyrosine‐Phosphorylated Proteins in Brain‐Derived Neurotrophic Factor Signal

Abstract

Brain-derived neurotrophic factor (BDNF), a member of the neurotrophins, promotes differentiation and survival and regulates plasticity of various types of neurons. BDNF binds to TrkB, a receptor tyrosine kinase, which results in the activation of a variety of signaling molecules to exert the various functions of BDNF. Shp-2, a Src homology 2 domain-containing cytoplasmic tyrosine phosphatase, is involved in neurotrophin signaling in PC12 cells and cultured cerebral cortical neurons. To examine the roles of Shp-2 in BDNF signaling in cultured rat cerebral cortical neurons, the wild-type and phosphatase-inactive mutant (C/S mutant) forms of Shp-2 were ectopically expressed in cultured neurons using recombinant adenovirus vectors. We found that several proteins tyrosinephosphorylated in response to BDNF showed enhanced levels of tyrosine phosphorylation in cultured neurons infected with C/S mutant adenovirus in comparison with those infected with the wild-type Shp-2 adenovirus. In addition, in immunoprecipitates with anti-Shp-2 antibody, we also observed at least four proteins that displayed enhanced phosphorylation in response to BDNF in cultured neurons infected with the C/S mutant adenovirus. We found that the Shp-2-binding protein, brain immunoglobulin-like molecule with tyrosine-based activation motifs (BIT), was strongly tyrosine-phosphorylated in response to BDNF in cultured neurons expressing the C/S mutant of Shp-2. In contrast, the level of BDNF-induced phosphorylation of mitogen-activated protein kinase and coprecipitated proteins with anti-Trk and Grb2 antibodies did not show any difference between neurons infected with these two types of Shp-2. Furthermore, the survival effect of BDNF was enhanced by the wild type of Shp-2, although it was not influenced by the C/S mutant of Shp-2. These results indicated that in cultured cerebral cortical neurons Shp-2 is specifically involved in the regulation of several tyrosine-phosphorylated proteins, including BIT, in the BDNF signaling pathway. In addition, the phosphatase Shp-2 may not influence the level of BDNF-induced activation of mitogen-activated protein kinase in cultured cortical neurons. Further, Shp-2 may have potential to positively regulate BDNF-promoting neuronal survival. Key Words: Neurotrophin-Adenovirus vector-Tyrosine phosphatase-TrkB.

BDNF contributes to the development of neuropathic pain by induction of spinal long-term potentiation via SHP2 associated GluN2B-containing NMDA receptors activation in rats with spinal nerve ligation

“…To clarify the underlying mechanisms by which how BDNF activates GluN2B-NMDA receptors in the spinal dorsal horn following spinal nerve injury, we focused on SHP2, a Src homology-2 (H2) domaincontaining protein tyrosine phosphatase-2, which has TrkB/TrkB and GluN2B-NMDA signaling pathway (Araki et al, 2000;Easton et al, 2006;Lin et al, 1999;Neel et al, 2003;Okada et al, 1996;Peng et al, 2012). We discovered that in intact rats, 7 days after intrathecal administration of BDNF (100 ng, twice per day for 2 days, see Fig.…”

“…SHP2, a Src homology-2 (H2) domain-containing protein tyrosine phosphatase-2, acting as a major regulator of receptor tyrosine kinase (Grossmann et al, 2010), has been implicated in numerous neurotrophin signaling (Case et al, 1994;Matozaki et al, 2009;Ohnishi et al, 1999;Stein-Gerlach et al, 1998), including BDNF/TrkB signaling pathway (Araki et al, 2000;Easton et al, 2006;Neel et al, 2003;Okada et al, 1996). In an in vitro study, Lin and colleagues have reported that SHP2 participates in BDNF-mediated GluN2B-NMDA receptors signaling at the postsynaptic site, and BDNF enhances association of SHP2 with the NMDA receptor subunit GluN2B in the cortical postsynaptic density (PSD) (Lin et al, 1999).…”

Protein phosphatases and their potential implications in neuroprotective processes

“…The tyrosine phosphatases SHP2 and PTPa increase Src activity by promoting Y527 dephosphorylation either indirectly for SHP2 by reducing the interaction of Src with the tyrosine kinase Csk [58] or directly for PTPa [59]. Despite this function, however, SHP2 was found to promote cell survival by mechanisms that are not well understood but that may involve enhancement of neurotrophin signalling [60][61][62]. SHP2 is expressed in various neurons in human and mouse adult brain [63,64] and is localized in pre-and postsynaptic membranes [65] and mitochondria [66].…”

Fluvoxamine and sigma-1 receptor agonists dehydroepiandrosterone (DHEA)-sulfate induces the Ser473-phosphorylation of Akt-1 in PC12 cells

“…BDNF is a 27-kDa polypeptide that binds to and activates tyrosine kinase receptor (TrkB) to exert their effects (Schlessinger and Ullrich 1992;Barbacid 1995;Weiss et al 1998). TrkB, once activated by ligands, stimulates the expression of PI3K (Araki et al 2000). The downstream target of phosphoinositide 3-kinase (PI3K) is Akt-1, a serine-threonine kinase, also referred to as protein kinase B (PKB).…”