Cytokine that stimulates the proliferation of hematopoietic stem cells and megakaryocyte progenitor cells and induces megakaryocyte maturation resulting in increased platelet production (PubMed:8913282). Also promotes the proliferation of hepatocytes in response to liver damage (PubMed:22253262). Binding to its receptor formed by IL6ST and either IL11RA1 or IL11RA2 activates a signaling cascade that promotes cell proliferation, also in the context of various cancers (PubMed:10026196, PubMed:23948300). Signaling leads to the activation of intracellular protein kinases and the phosphorylation of STAT3 (PubMed:23948300, PubMed:22253262). The interaction with the membrane-bound IL11RA and IL6ST stimulates 'classic signaling', whereas the binding of IL11 and soluble IL11RA to IL6ST stimulates 'trans-signaling' (By similarity). Interacts with either IL11RA1 or IL11RA2 to associate with IL6ST, giving rise to a multimeric signaling complex. Up-regulated in hepatocytes by oxidative stress caused by liver damage. Belongs to the IL-6 superfamily.