title: Two PTP receptors mediate CSPG inhibition by convergent and divergent signaling pathways in neurons.
abstract: Receptor protein tyrosine phosphatase σ (PTPσ) and its subfamily member LAR act as transmembrane receptors that mediate growth inhibition of chondroitin sulfate proteoglycans (CSPGs). Inhibition of either receptor increases axon growth into and beyond scar tissues after CNS injury. However, it is unclear why neurons express two similar CSPG receptors, nor whether they use the same or different intracellular pathways. We have now studied the signaling pathways of these two receptors using N2A cells and primary neurons derived from knockout mice. We demonstrate that both receptors share certain signaling pathways (RhoA, Akt and Erk), but also use distinct signals to mediate CSPG actions. Activation of PTPσ by CSPGs selectively inactivated CRMP2, APC, S6 kinase and CREB. By contrast LAR activation inactivated PKCζ, cofilin and LKB1. For the first time, we propose a model of the signaling pathways downstream of these two CSPG receptors. We also demonstrate that deleting both receptors exhibits additive enhancement of axon growth in adult neuronal cultures in vitro. Our findings elucidate the novel downstream pathways of CSPGs and suggest potential synergy of blocking their two PTP receptors.
authors.affiliation: Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.|Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Ohtake
authors.affiliation: Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
authors.forename: Daniella
authors.initials: D
authors.lastname: Wong
authors.affiliation: Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.|Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
authors.forename: P M
authors.initials: PM
authors.lastname: Abdul-Muneer
authors.affiliation: Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.|Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
authors.forename: Michael E
authors.initials: ME
authors.lastname: Selzer
authors.affiliation: Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.|Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA.
authors.forename: Shuxin
authors.initials: S
authors.lastname: Li
mesh_terms: D000818:Animals; D002460:Cell Line; D011508:Chondroitin Sulfate Proteoglycans / Q000235:genetics / Q000378:metabolism*; D020935:MAP Kinase Signaling System / Q000502:physiology*; D051379:Mice; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5 / Q000235:genetics / Q000378:metabolism*
chemical_list: D011508:Chondroitin Sulfate Proteoglycans; D011494:Protein Kinases; D054633:Receptor-Like Protein Tyrosine Phosphatases, Class 5