title: Proteolytic processing of the receptor-type protein tyrosine phosphatase PTPBR7.
abstract: The single-copy mouse gene Ptprr gives rise to different protein tyrosine phosphatase (PTP) isoforms in neuronal cells through the use of distinct promoters, alternative splicing, and multiple translation initiation sites. Here, we examined the array of post-translational modifications imposed on the PTPRR protein isoforms PTPBR7, PTP-SL, PTPPBSgamma42 and PTPPBSgamma37, which have distinct N-terminal segments and localize to different parts of the cell. All isoforms were found to be short-lived, constitutively phosphorylated proteins. In addition, the transmembrane isoform, PTPBR7, was subject to N-terminal proteolytic processing, in between amino acid position 136 and 137, resulting in an additional, 65-kDa transmembrane PTPRR isoform. Unlike for some other receptor-type PTPs, the proteolytically produced N-terminal ectodomain does not remain associated with this PTPRR-65. Shedding of PTPBR7-derived polypeptides at the cell surface further adds to the molecular complexity of PTPRR biology.
authors.affiliation: Department of Cell Biology, Nijmegen Centre for Molecular Life Sciences, Radboud University Nijmegen Medical Centre, the Netherlands.
authors.forename: Gönül
authors.initials: G
authors.lastname: Dilaver
authors.forename: Rinske
authors.initials: R
authors.lastname: van de Vorstenbosch
authors.forename: Céline
authors.initials: C
authors.lastname: Tárrega
authors.forename: Pablo
authors.initials: P
authors.lastname: Ríos
authors.forename: Rafael
authors.initials: R
authors.lastname: Pulido
authors.forename: Karlijn
authors.initials: K
authors.lastname: van Aerde
authors.forename: Jack
authors.initials: J
authors.lastname: Fransen
authors.forename: Wiljan
authors.initials: W
authors.lastname: Hendriks
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010766:Phosphorylation; D020033:Protein Isoforms / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D017027:Protein Tyrosine Phosphatases / Q000378:metabolism*; D054634:Receptor-Like Protein Tyrosine Phosphatases, Class 7; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D020033:Protein Isoforms; D011993:Recombinant Fusion Proteins; D017027:Protein Tyrosine Phosphatases; C513472:Ptprr protein, mouse; D054634:Receptor-Like Protein Tyrosine Phosphatases, Class 7