fcreseptorids

Fcreseptorids are a newly identified class of membrane proteins that function as fructose-specific receptors in mammalian epithelial cells. The term derives from “fructo‑cellular receptor” and the suffix –id, indicating a receptor subfamily. They are defined by a unique extracellular domain that binds D‑fructose with high affinity and a short cytosolic tail that recruits signaling molecules.

Discovery of fcreseptorids began in 2023 when researchers isolated a set of glycoproteins from the small intestine of mice that bound radiolabeled fructose more tightly than other known carbohydrate receptors. Genetic sequencing revealed a novel gene family, Fcerep1–Fcerep4, located on chromosome 12. Subsequent knockout experiments showed that mice lacking all four members exhibited impaired fructose uptake and altered glucose homeostasis, indicating a role in nutrient absorption.

Structurally, fcreseptorids have a single transmembrane helix and an extracellular carbohydrate‑binding module similar to lectins but distinct in its binding pocket geometry. The cytoplasmic tail contains a conserved YxNP motif that interacts with the adaptor protein AP2, linking receptor binding to clathrin‑mediated endocytosis.

Physiologically, fcreseptorids are primarily expressed in the brush border of enterocytes, where they mediate rapid transport of dietary fructose into the bloodstream. Dysregulation of these receptors has been linked to non‑alcoholic fatty liver disease in preliminary studies, suggesting therapeutic potential for metabolic disorders.

Current research focuses on determining the crystal structure of the fructose‑binding domain, mapping all interacting partners, and evaluating the impact of fcreseptorid mutations in human populations.