In contrast to the ubiquitous role of long RIM family members, RIM4 does not act by modulating release. (A) Representative miniature excitatory postsynaptic current (mEPSC) recordings from RIM4 wild-type (WT, black) and KO_const (grey) mice. Scale bars = 2 s (horizontal) and 2 pA (vertical). (B and C) Cumulative distribution function (CDF) histograms of mean amplitude (B) and inter-event interval (C) of mEPSCs. n mice/n cells: WT 8/12, KO_const 4/5. (D) Representative traces of field excitatory postsynaptic potentials (fEPSPs) of RIM4 WT (black) and KO_const (grey) (left) and bar graph showing the mean paired-pulse ratio (PPR) (right). n mice/n cells: WT 8/32, KO_const 4/9, unpaired t-test. (E) Example images and quantification of immunoblots of hippocampal lysates from RIM4 WT and KO_const mice labelled with antibodies against RIM4, RIM1, RIM3, Liprin-α, PSD95 and β-actin. n = 5 per group. KO = knockout.