FAM83

FAM83, short for family with sequence similarity 83, designates a family of cytoplasmic proteins in vertebrates that are defined by sequence similarity rather than a single enzymatic function. In humans the family comprises eight coding genes—FAM83A through FAM83H—found at separate chromosomal loci. The name reflects the shared but diverse amino-acid sequences among member proteins, which are conserved across vertebrates, indicating an ancient origin.

All FAM83 proteins share a conserved N-terminal domain, referred to as DUF1669, and most possess a coiled-coil rich C-terminal region that supports protein-protein interactions and subcellular localization, typically in the cytoplasm.

Functionally, FAM83 proteins participate in signaling networks that govern cell growth, differentiation and movement. They are considered modulators or scaffolds of signaling pathways rather than enzymes. Several members have been implicated in epidermal growth factor receptor (EGFR) and Ras-RAF-MAPK signaling, and genetic or expression alterations in FAM83 genes have been observed in various cancers. Some family members can influence sensitivity or resistance to targeted therapies in tumor cells, although the mechanistic details can be context-dependent.

Specific FAM83 members have been studied more than others. For example, FAM83A has been associated with EGFR pathway activity, and FAM83B with maintenance of MAPK signaling in certain cancers. Overall, the FAM83 family represents a conserved group of cytoplasmic regulators whose precise roles are still being defined.