RTKN-1-CT is imperative for RTKN-1 oligomerization. (A) Domain architecture of RTKN-1a and fragments, including RBD, RBD-PH, PH-CT, CT, and ΔPRM. Δ indicates deletion. (B) Western blot showing GST pulldown with in vitro–translated HA-tagged RTKN-1. (C and C′) Western blot showing GST pulldown with in vitro–translated HA-tagged RTKN-1-CT. (D) Western blot showing GST pulldown with in vitro–translated HA-RBD-PH. (E) Western blot showing GST pulldown with in vitro translated HA-RTKN-1 ΔPRM. (F) SDS-PAGE of purified HA-RBD-PH and HA-RTKN-1. (G) Gradient SDS-PAGE of covalently crosslinked HA-RBD-PH and HA-RTKN-1.