FAM3A, FAM3B, FAM3C and FAM3D are members of the “family with sequence similarity 3” (FAM3) gene family, an emerging class of cytokine-like proteins with a unique structural globular β-β-α fold and distinct biological functions. With widespread expression in tissue, organs and in many cell types, their specific roles in human diseases have been the focus of much research. FAM3A acts as a positive regulator of metabolic health, typically activating canonical pro-survival and metabolic pathways. FAM3B, also called PANDER (PANcreatic DERived Factor), exerts critical physiological functions in the regulation of glycemic levels via promotion of hepatic glucose production and pancreatic β-cell insulin secretion. FAM3C, also named ILEI (Interleukin-like EMT inducer), is involved as an inducer of epithelial–mesenchymal transition (EMT) and cancer metastasis, as well as osteoblast differentiation and bone mineralization. FAM3D is a gut-secreted protein and potential regulator of gastrointestinal homeostasis and microbiota-induced inflammation. Here we provide an overview of previous studies supporting that FAM3 proteins act through putative membrane receptors and co-partners, including fibroblast growth factor receptor (FGFR), leukemia inhibitory factor receptor (LIFR), formyl peptide receptor (FPR1/2), to activate diverse downstream signaling pathways on different cellular contexts. Basic and clinical studies suggest that the FAM3 family influences both obesity, diabetes, and other metabolic disorders; thus, its expression may have diagnostic potential. The differential and often cancer-specific expression patterns make members of the FAM3 family promising candidates for biomarkers and therapeutic targets of some types of neoplasia.
Belizário et al. (Mon,) studied this question.