Figure 8.

Analysis of the interaction of PTPδ or LAR with Nrxn1α^-SS4. A, Representative images of cell-surface binding assays. HEK293T cells expressing the indicated HA-tagged LAR-RPTP splice variants were incubated with 10 μg/ml of control IgC or Ig-Nrxn1α^-SS4 and then analyzed by immunofluorescence imaging of Ig-fusion proteins (red) and HA antibodies (green). Scale bar, 10 μm. B, Representative images of cell-surface binding assays. HEK293T cells expressing HA-PTPσ splice variants or HA-PTPδ were incubated with 10 μg/ml of control IgC or Ig-Nrxn3α^-SS4 and then analyzed by immunofluorescence imaging of Ig-fusion proteins (red) and HA antibodies (green). Scale bar, 10 μm. C, D, Quantitation of average red intensities in the green positive region of HEK293T cells in A. n indicates the number of cells as follows: Ig-Nrxn1α/PTPδ Ig^A–B–, n = 23; Ig-Nrxn1α/PTPδ Ig^A+B–, n = 21; Ig-Nrxn1α/PTPδ Ig^A–B+, n = 26; Ig-Nrxn1α/PTPδ Ig^A+B+, n = 25; Ig-Nrxn1α/LAR Ig^A–B–, n = 24; Ig-Nrxn1α/LAR Ig^A+B–, n = 23; Ig-Nrxn1α/LAR Ig^A–B+, n = 25; IgC/PTPδ Ig^A–B–, n = 10; IgC/PTPδ Ig^A+B–, n = 10; IgC/PTPδ Ig^A–B+, n = 10; IgC/PTPδ Ig^A+B+, n = 11; IgC/LAR Ig^A–B–, n = 10; IgC/LAR Ig^A+B–, n = 12; and IgC/LAR Ig^A–B+, n = 13. Quantitation of average red intensities in the green positive region of HEK293T cells in B. n indicates the number of cells as follows: Ig-Nrxn3α/PTPσ^A–B–, n = 16; Ig-Nrxn3α/PTPσ^A+B–, n = 15; Ig-Nrxn3α/PTPσ^A–B+, n = 15; Ig-Nrxn3α/PTPσ^A+B+, n = 14; Ig-Nrxn3α/PTPδ^A+B+, n = 19; IgC/PTPσ^A–B–, n = 14; IgC/PTPσ^A+B–, n = 8; IgC/PTPσ^A–B+, n = 13; IgC/PTPσ^A+B+, n = 13; and IgC/PTPδ^A+B–, n = 8.