Plexin B3 interacts with Rin in the Sos recruitment system. Various pMyr and pSos plasmid combinations (as indicated on the left) were used for co-transformation of cdc25H yeast cells representing a positive control (line 1) and negative controls (lines 2–7, 10). Six independent transformants were spotted and grown for six days on glucose medium at 22°C (left panel) or 37°C (middle panel), and on galactose medium at 37°C (right panel). Cdc25H cells re-transformed with pSos-B3IC and pMyr-Rin (line 8) grow on galactose medium at 37°C for six days (right panel), showing interaction between full length human Rin and the intracellular part of human B3 in this system. Cells re-transformed with pSos-B2IC and pMyr-Rin (line 9) show no growth on galactose medium at 37°C after six days (right panel), demonstrating that the intracellular part of human B2 and human Rin do not interact in this system. Rin co-transfected with pSos-vector without insert is not able to induce growth on galactose at 37°C (line 10).