C1ql2 and C1ql3 from mossy fibers (MFs) locate at MF-CA3 synapses in hippocampus
C1ql2/3 directly bind to the GluK2 and GluK4 kainate receptors (KARs)
Neurexin3 binds C1ql2/3 via the splice site 5 sequence and accumulates KARs
C1ql2/3 serve as master regulators of postsynaptic KAR complexes in CA3 neurons