IL-34 (Interleukin-34) is a cytokine that promotes the differentiation and viability of monocytes and macrophages. Stimulates phosphorylation of MAPK1/ERK2 AND MAPK3/ERK1. Ligand for colony-stimulating factor-1 receptor CSF1R. It is detected in the sinusoidal epithelium in the red pulp of spleen. Predominantly e, Xenopus/Amphibian,pressed in spleen. Also detected in a range of other tissues including heart, brain, lung, liver, kidney, thymus, testis, ovary, small intestine,Porcinerostate and colon.