Fyn ELISA Kit

Background: Chondroitin sulfate (CS) chains are prominent extra/pericellular matrix components in the central nervous system (CNS) and can exert positive or negative regulatory effects on neurite outgrowth, depending on the CS structure and the amount. Despite the remarkable abilities of highly sulfated forms of CS chains to enhance neurite outgrowth, the neuronal recognition systems for such promotional CS chains, including CS-D polysaccharide, remain to be fully elucidated. Methods: We explored the molecular basis of the CS-D-mediated neurite extension using primary hippocampal neurons cultured on substrate precoated with CS-D polysaccharides, and evaluated functional involvement of a distinct integrin heterodimer as a novel neuronal CS receptor for CS-D. Results: We identified an extracellular matrix receptor, integrin alpha v beta 3, as a functional receptor for CS-D. CS-D, but not CS-C (a precursor form of CS-D) showed significant binding affinity toward recombinant integrin alpha v beta 3 heterodimer and activated intracellular signaling(s) involving focal adhesion kinase (FAK) and Src/Fyn kinase. Functional blockade of the respective players for integrin signaling abrogated the promotional effects of CS-D. We also found the existence of CS-D-induced integrin activation system in neuronal stem/progenitor cell population. Conclusions: The neuronal cell surface integrin alpha v beta 3 can function as a CS receptor for a highly sulfated CS subtype, CS-D. General significance: Our findings are the first to demonstrate that CS-dependent neurite-outgrowth promotion is exerted via direct activation of specific integrin heterodimers on neuronal cell surfaces, providing new insights into understanding the CS-sensing machineries that regulate CNS development and regeneration.

5-HT4R, 5-HT6R, and 5-HT7AR are three constitutively active G(s)-coupled 5-HT receptors that have key roles in brain development, learning, memory, cognition, and other physiological processes in the central nervous system. In addition to G(s) signaling cascade mediated by these three 5-HT receptors, the ERK1/2 signaling which is dependent on cyclic adenosine monophosphate (cAMP) production and protein kinase A (PKA) activation downstream of G(s) signaling has also been widely studied. In this study, we investigated these two signaling pathways originating from the three G(s)-coupled 5-HT receptors in AD293 cells. We found that the phosphorylation and activation of ERK1/2 are ligand-induced, in contrast to the constitutively active G(s) signaling. This indicates that G(s) signaling alone is not sufficient for ERK1/2 activation in these three 5-HT receptors. In addition to G(s), we found that beta-arrestin and Fyn are essential for the activation of ERK1/2. Together, these results put forth a novel mechanism for ERK1/2 activation involving the cooperative action of G(s), beta-arrestin, and Fyn.