Fig 2: PTPRZ mRNA is highly expressed in brain tumors. (A–F) PTPRZ (A–C) and PTPRG (D–F) mRNA levels in the GSE15824 (A and D), GSE4290 (B and E), and GSE108524 (C and F) RNA microarray datasets. All data, corresponding with the gene expression levels, are normalized signals and are presented as the mean ± SEM, with individual data points represented by circles. **P < .01, ****P < .0001 by Mann–Whitney U test (C and F), one-way ANOVA with Dunnett’s test (B), and Kruskal–Wallis test with Dunn’s test (A, D, and E).

Fig 3: Characterization of R-PTP-zeta expression in vivo. Left, Immuno-histochemical staining of rat brain at P66 for the presynaptic marker Bassoon, excitatory postsynaptic marker Homer and R-PTP-zeta (grey in single color images). Right, yellow in the merged composite (top) image indicates co-expression of Homer (red) and R-PTP-zeta (green). Yellow in the bottom merged image indicates co-expression of Bassoon (red) and R-PTP-zeta (green).

Fig 4: Western blot analysis of PTPRZ and sPTPRZ in microsomal fractions and CSF from glioma patients reveals 2 forms. (A) CSF samples from glioma patients A and B were treated with or without chondroitinase ABC (Chase ABC) and probed with Santa Cruz or Sigma anti-PTPRZ antibodies. (B) Schematic of the structures of PTPRZ-Long, PTPRZ-Short, and their proteolytic cleaved forms, sPTPRZ-Long and sPTPRZ-Short, respectively. Regions recognized by the anti-PTPRZ1 (Sigma), anti-PTPRZ (Santa Cruz), and Cat-315 antibodies used are indicated. (C) Microsomal fractions prepared from glioma tissues and CSF samples were treated with or without chondroitinase ABC (Chase ABC) and used for western blot analysis with anti-PTPRZ (Santa Cruz), Cat-315, and anti-Aggrecan antibodies. Cadherin and TTR were probed as loading controls for microsomal fractions and CSF, respectively. A and B are from different patients. (D) Western blot analysis of CSF samples from a glioma patient treated with chondroitinase ABC (Chase ABC) or endo-ß-galactosidase and probed with anti-PTPRZ (Santa Cruz).

Fig 5: Characterization of R-PTP-zeta expression and synaptic markers in vitro. (A) Immunostaining for Bassoon, R-PTP-zeta, and SynCAM 1 in cultured neurons. R-PTP-zeta (grey in single color image) and SynCAM 1 (grey in single color image) were stained under non-permeabilizing conditions using antibodies detecting extracellular epitopes and Bassoon (grey in single color image) was stained under permeabilizing conditions. Yellow in larger composite (left) image indicates colocalization of Bassoon (red) and extracellular R-PTP-zeta (green). White in larger composite (right) image indicates colocalization of extracellular SynCAM 1 (magenta) and extracellular R-PTP-zeta (green). Panels below show enlarged dendritic segments from the composite images to visualize colocalization (arrowheads). (B) Immunostaining for Homer and R-PTP-zeta and SynCAM 1 in cultured neurons. Extracellular R-PTP-zeta (grey in single color image) and SynCAM 1 (grey in single color image) were immunostained under non-permeabilizing conditions as in (A) and Homer (grey in single color image) was immunodetected under permeabilizing conditions. Yellow in larger composite image (left) indicates colocalization of Homer (red) and extracellular R-PTP-zeta (green). White in larger composite image (right) indicates colocalization of extracellular SynCAM 1 (magenta) and extracellular R-PTP-zeta (green). Panels below show enlarged dendrites from the composite images. Arrowheads mark sites of colocalization.