• BMB Reports
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• 제48권5호
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• pp.249-255
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• 2015

PTPRT/RPTPρ is the most recently isolated member of the type IIB receptor-type protein tyrosine phosphatase family and its expression is restricted to the nervous system. PTPRT plays a critical role in regulation of synaptic formation and neuronal development. When PTPRT was overexpressed in hippocampal neurons, synaptic formation and dendritic arborization were induced. On the other hand, knockdown of PTPRT decreased neuronal transmission and attenuated neuronal development. PTPRT strengthened neuronal synapses by forming homophilic trans dimers with each other and heterophilic cis complexes with neuronal adhesion molecules. Fyn tyrosine kinase regulated PTPRT activity through phosphorylation of tyrosine 912 within the membrane-proximal catalytic domain of PTPRT. Phosphorylation induced homophilic cis dimerization of PTPRT and resulted in the inhibition of phosphatase activity. BCR-Rac1 GAP and Syntaxin-binding protein were found as new endogenous substrates of PTPRT in rat brain. PTPRT induced polymerization of actin cytoskeleton that determined the morphologies of dendrites and spines by inhibiting BCR-Rac1 GAP activity. Additionally, PTPRT appeared to regulate neurotransmitter release through reinforcement of interactions between Syntaxin-binding protein and Syntaxin, a SNARE protein. In conclusion, PTPRT regulates synaptic function and neuronal development through interactions with neuronal adhesion molecules and the dephosphorylation of synaptic molecules. [BMB Reports 2015; 48(5): 249-255]

• 대한한의학방제학회지
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• 제29권4호
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• pp.191-203
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• 2021

Objectives : In this study, we investigate the anti-allergic effects of Ullmus macrocarpa Hance (Ulmus) on RBL-2H3 mast cell (basophilic leukemia cell line), which are mediated by FcεRIs. Methods : We evaluated the effect of the ethanol extract of Ulmus on the allergic inflammatory response in IgE-antigen-mediated RBL-2H3 cells. Cell toxicity was determined by MTT assay and the markers of degranulation such as beta-hexosaminidase, histamine, PGD2, TNF-α, IL-4, IL-6 production of inflammatory mediators and FcεRI-mediated protein expression by western blot. Results : Ulmus inhibited degranulation and production of allergic mediators (e.g., TNF-α, IL-4, and IL-6) in them. Ulmus reduced histamine levels, expression of FcεRI signaling-related genes such as Lyn, Syk, and Fyn, and extracellular signal-regulated kinase phosphorylation in mast cells. Also, Ulmus reduced PGD2 release and cyclooxygenase-2 expression, and cytosolic phospholipase A2 phosphorylation in FcεRI-mediated RBL-2H3 mast cells. Conclusions : These results indicate that Ulmus exhibits anti-allergic activity through inhibition of degranulation and inflammatory mediators and cytokine release. These findings suggest that Ulmus may have potential as a prophylactic and therapeutic agent for the treatment of various allergic diseases.