Receptor for TNFSF4/OX40L/GP34. Is a costimulatory molecule implicated in long-term T-cell immunity (By similarity). Interacts with TRAF2, TRAF3 and TRAF5. Expressed in CD4(+) T-cells and in T-helper Th17 cells (at protein level). By IL6/STAT3 signaling in T-helper Th17 cells.