Uncharacterized protein C17orf78 (C17orf78)

Uncharacterized protein C17orf78 (C17orf78), also called famsin, is a protein highly expressed in the human small intestine, particularly the duodenum[1]. It is a single-pass transmembrane protein, cleaved and secreted as a hormone upon fasting and low-glucose conditions[2]. Famsin promotes metabolic adaptations to fasting by binding to the olfactory receptor OLFR796, activating calcium signaling, gluconeogenesis, ketogenesis, and induction of torpor. Loss of famsin or its receptor impairs these adaptations; conversely, neutralizing famsin improves blood glucose control in diabetic models, indicating its potential as a therapeutic target for metabolic diseases like diabetes. Its precise cellular sources, subcellular dynamics, and downstream physiological consequences are still being studied. No approved drugs directly target C17orf78/famsin, but its signaling pathway represents a novel axis for metabolic regulation research[2].

Other names

C17orf78chromosome 17 open reading frame 78famsinFLJ39647uncharacterized protein C17orf78

Not a known drug target yet; mechanism involves secretion (by furin cleavage), followed by binding to olfactory receptor OLFR796, activating Gαq/11 and intracellular calcium signaling, leading to metabolic effects (increased gluconeogenesis and ketogenesis)