Glycobiology Advance Access originally published online on September 13, 2006
Glycobiology 2007 17(1):10-24; doi:10.1093/glycob/cwl049
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Dependence of neurotrophic factor activation of Trk tyrosine kinase receptors on cellular sialidase
2 Department of Microbiology and Immunology, Queen's University, Kingston, Ontario, Canada, K7L3N6
3 Fundamental and Applied Molecular Biology, Ghent University, Flanders Interuniversity Institute for Biotechnology (V.I.B.) Technologiepark 927 B-9052 Gent-Zwijnaarde, Belgium
1 To whom correspondence should be addressed; Tel.: +1-613-533-2457; Fax: +1-613-533-6796; e-mail: szewczuk{at}post.queensu.ca
Received on March 30, 2006; revised on August 14, 2006; accepted on September 8, 2006
A direct link between receptor glycosylation and activation following natural ligand interaction has not been observed. Here, we discover a membrane sialidase-controlling mechanism that depends on ligand binding to its receptor to induce enzyme activity which targets and desialylates the receptor and, consequently, causes the induction of receptor dimerization and activation. We also identify a specific sialyl
-2,3-linked ß-galactosyl sugar residue of TrkA tyrosine kinase receptor, which is rapidly targeted and hydrolyzed by the sialidase. Trk-expressing cells and primary cortical neurons following stimulation with specific neurotrophic growth factors express a vigorous membrane sialidase activity. Neuraminidase inhibitors, Tamiflu, BCX1812, and BCX1827, block sialidase activity induced by nerve growth factor (NGF) in TrkA-PC12 cells and by brain-derived neurotrophic factor (BDNF) in primary cortical neurons. In contrast, the neuraminidase inhibitor, 2-deoxy-2,3-dehydro-N-acetylneuraminic acid, specific for plasma membrane ganglioside Neu3 and Neu2 sialidases has no inhibitory effect on NGF-induced pTrkA. The GM1 ganglioside specific cholera toxin subunit B applied to TrkA-PC12 cells has no inhibitory effect on NGF-induced sialidase activity. Neurite outgrowths induced by NGF-treated TrkA-PC12 and BDNF-treated PC12nnr5 stably transfected with TrkB receptors (TrkB-nnr5) cells are significantly inhibited by Tamiflu. Our results establish a novel mode of regulation of receptor activation by its natural ligand and define a new function for cellular sialidases.
Key words: cell differentiation / cell signaling / receptor activation / sialic acid / TrkA tyrosine kinase receptor / trypanosome trans-sialidase / cellular sialidase
The authors declare that they have no competing financial interests.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
A. Woronowicz, S. R. Amith, V. W Davis, P. Jayanth, K. De Vusser, W. Laroy, R. Contreras, S. O Meakin, and M. R Szewczuk Trypanosome trans-sialidase mediates neuroprotection against oxidative stress, serum/glucose deprivation, and hypoxia-induced neurite retraction in Trk-expressing PC12 cells Glycobiology, July 1, 2007; 17(7): 725 - 734. [Abstract] [Full Text] [PDF] |
||||
