International Journal Of Bilogical Sciences
.: Home > International Journal Of Bilogical Sciences > 2011 > Volume 7 Number 7 > Irene M. Chesini 1, Griet Debyser 2, Huib Croes 1, Gerdy B. ten Dam 3, Bart Devreese 2, Andrew W. Stoker 4 and Wiljan J.A.J. Hendriks 1,
PTPBR7 Binding Proteins in Myelinating Neurons of the Mouse Brain
Irene M. Chesini 1, Griet Debyser 2, Huib Croes 1, Gerdy B. ten Dam 3, Bart Devreese 2, Andrew W. Stoker 4 and Wiljan J.A.J. Hendriks 1,
1. Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands 2. Department of Biochemistry and Microbiology, Ghent University, K.L. Ledeganckstraat 35, 9000 Gent, Belgium 3. Department of Biochemistry, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Cen-tre, Geert Grooteplein 28, 6525 GA Nijmegen, The Netherlands 4. Neural Development Unit, UCL, Institute of Child Health, 30 Guildford Street, London, UK
Mouse protein tyrosine phosphatase PTPBR7 is a receptor-like, transmembrane protein that is localized on the surface of neuronal cells. Its protein phosphatase activity is reduced upon multimerization, and PTPBR7-deficient mice display motor coordination defects. Extracellular molecules that may influence PTPBR7 activity, however, remain to be determined. We here show that the PTPBR7 extracellular domain binds to highly myelinated regions in mouse brain, in particular the white matter tracks in cerebellum. PTPBR7 deficiency does not alter this binding pattern, as witnessed by RAP in situ staining of Ptprr-/- mouse brain sections. Additional in situ and in vitro experiments also suggest that sugar moieties of heparan sulphate and chondroitin sulphate glycosaminoglycans are not critical for PTPBR7 binding. Candidate binding proteins were affinity-purified exploiting the PTPBR7 extracellular domain and iden-tified by mass spectrometric means. Results support the suggested link between PTPRR isoforms and cerebellar calcium ion homeostasis, and suggest an additional role in the process of cell-cell adhesion.
cerebellum; RAP in situ; extracellular domain; ligand protein; PTPRR; protein tyrosine phosphatase; mass spectrometry.
Date Deposited : 23 Sep 2011 14:40
Official URL: http://www.biolsci.org/
Last Modified : 23 Sep 2011 14:40
Volume 7, Number 7, - 2011
Full Text Original