RT Journal Article SR Electronic T1 Defining the relevant combinatorial space of the PKC/CARD-CC signal transduction nodes JF bioRxiv FD Cold Spring Harbor Laboratory SP 228767 DO 10.1101/228767 A1 Jens Staal A1 Yasmine Driege A1 Mira Haegman A1 Styliani Iliaki A1 Rudi Beyaert YR 2017 UL http://biorxiv.org/content/early/2017/12/04/228767.abstract AB Biological signal transduction typically display a so-called bow-tie or hour glass topology: Multiple receptors lead to multiple cellular responses but the signals all pass through a narrow waist of central signaling nodes. One such critical signaling node for several inflammatory and oncogenic signaling pathways in humans are the CARD-CC/Bcl10/MALT1 (CBM) complexes, which get activated by upstream protein kinase C (PKC). In humans, there are four phylogenetically distinct CaRD-CC family (CARD9, −10, −11 and −14) proteins and 9 true PKC isozymes (α to ι). At this moment, less than a handful of PKC/CARD-CC relationships are known from experimental evidence. In order to explore the biologically relevant combinatorial space out of all 36 potential permutations in this two-component signaling event, we made use of CRISPR/Cas9 genome-edited HEK293T cells to knock out CARD10 for subsequent pairwise co-transfections of all CARD-CC family members and activated mutants of all true PKCs. By quantitative reporter gene expression readout, we could define specific strong and weak PKC/CARD-CC relationships. Surprisingly as many as 21 PKC/CARD-CC combinations were found to have synergistic effects. This information will be valuable for future studies of novel signaling pathways dependent on the CBM complex signaling nodes. The expanded scope of signaling pathways can also have practical applications, where the information can be exploited for pharmacological manipulation of the signaling pathways via downstream components like MALT1 protease activity for more specific effects and potentially less of the side effects associated with PKC inhibition.