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Our review on p75 neurotrophin signaling in nervous system injury has been made available as a paper in press in the Trends In Neurosciences web site.
Injury or insult to the adult nervous system often results in reactivation of signaling pathways that are normally only active during development. The p75 neurotrophin receptor (p75NTR) is one such signaling molecule whose expression increases markedly following neural injury in many of the same cell types that express p75NTR during development. A series of studies during the past decade has demonstrated that p75NTR signaling contributes to neuronal and glial cell damage, axonal degeneration and dysfunction during injury and cellular stress. Why the nervous system reacts to injury by inducing a molecule that aids the demise of cells and axons is a biological paradox that remains to be explained satisfactorily. On the other hand, it may offer unique therapeutic opportunities for limiting the severity of nervous system injury and disease.
Read the full paper HERE.
The Journal of Cell Science publishes today our paper on the interaction between MET and GDNF signaling in the control of cortical GABAergic interneuron development (Perrinjaquet et al. 2011). This work demonstrates that responsiveness to GDNF in Gfra1 knock-out GABAergic interneurons can be restored upon addition of soluble GFRa1. As these neurons express neither RET nor NCAM, this result is only compatible with the existence of a novel transmembrane receptor partner for the GDNF-GFRa1 complex in GABAergic interneurons. Neither ErbB4 nor MET were found to fullfil this role. Unexpectedly, however, inhibition of MET (or its ligand HGF) per se promoted neuronal differentiation and migration and enhanced the activity of GDNF on GABAergic neurons. In agreement with this, Met mutant neurons showed enhanced responsiveness to GDNF and elevated levels of GFRa1 expression, both in vitro and in vivo. These results demonstrate the existence of a novel transmembrane receptor partner for the GDNF–GFRa1 complex and uncover an unexpected interplay between GDNF–GFRa1 and HGF–MET signaling in the early diversification of cortical GABAergic interneuron subtypes. Read the full paper HERE.
Our latest paper has been made available today at the Papers In Press site of the Journal of Biological Chemistry (Perrinjaquet et al. JBC 2010). This work identifies the protein tyrosine phosphatase SHP2 as a novel direct interactor of the receptor tyrosine kinase RET. SHP2 is the first effector known to bind to phosphorylated Tyr687 in the juxtamembrane region of the receptor. SHP2 recruitment contributes to the ability of RET to activate the PI3K/AKT pathway and promote survival and neurite outgrowth in primary neurons. Together with other findings, this work establishes SHP2 as a novel positive regulator of the neurotrophic activities of RET, and reveal Tyr687 as a critical platform for integration of RET signals. We anticipate that several other phospho-tyrosines of unknown function in neuronal receptor tyrosine kinases will also support similar regulatory functions. Read the full paper HERE.
Honoring the 200 anniversary of the Karolinska Institute, Biochemical and Biophysical Research Communications (BBRC) has published a special issue with a series of mini-reviews from KI scientists illustrating recent developments within some areas of biomedical research at the molecular level that have been actively pursued at KI. Our contribution, entitled “Beyond the cell surface: New mechanisms of receptor function“, discusses novel aspects of receptor signaling based on some of our recent investigations of the GDNF/GFRa1 signaling system.
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