Interleukin-34 (IL34) can bind Syndecan-1 (SDC1), a cell surface proteoglycan. Low levels of SDC1 may sequester IL34 at the cell surface and prevent it from binding Macrophage colony-stimulating factor 1 receptor (CSF1R), while high SDC1 levels may facilitate IL34-CSF1R signaling (Segaliny et al. 2015). Ultimately, these events lead to the release of pro-inflammatory chemokines regulating the innate immunity and inflammation. The precise interaction between IL34:SDC1 and CSF1R is unknown. Hence, this interaction is represented as an uncertain black box event.
Le Goff, B,