POFUT1 Human
Description
Introduction to POFUT1
POFUT1 (Protein O-Fucosyltransferase 1) is a glycosyltransferase enzyme encoded by the POFUT1 gene on chromosome 20q11. It catalyzes the addition of fucose (a monosaccharide) to serine or threonine residues within epidermal growth factor-like (EGF) repeats of transmembrane proteins, including Notch receptors. This post-translational modification is critical for Notch receptor-ligand interactions and downstream signaling, which regulate cell fate, proliferation, and differentiation .
Enzymatic Mechanism
POFUT1 resides in the endoplasmic reticulum, where it transfers fucose from GDP-β-L-fucose to conserved serine/threonine residues in EGF domains. This activity is essential for Notch receptor maturation and signaling. Key structural features include:
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Substrate specificity: Requires properly folded EGF domains with conserved cysteine residues.
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Active site: Interacts with GDP-fucose via conserved residues (e.g., R43, D244), facilitating sugar transfer .
Role in Notch Signaling
POFUT1-mediated fucosylation enables Notch receptors to bind ligands (e.g., Delta, Jagged) and undergo γ-secretase-mediated cleavage, releasing the Notch intracellular domain (NICD) for nuclear transcriptional activation .
Normal Physiological Functions
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Developmental processes: Critical for somitogenesis, cardiogenesis, and neurogenesis .
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Skin homeostasis: Maintains melanocyte-keratinocyte interactions .
Pathological Implications
CRC Progression
Studies using CRC cell lines (SW620, HCT116) demonstrated that POFUT1 knockdown reduces:
Mechanistically, POFUT1 silencing suppresses NICD nuclear translocation and Notch1 target genes (e.g., HES1) .
Dowling-Degos Disease (DDD2)
Mutations in POFUT1 (e.g., R43H, Y73C) disrupt enzymatic activity, leading to:
Therapeutic Potential
POFUT1 inhibition has emerged as a strategy for cancers driven by Notch1 mutations (e.g., leukemias) . Structural studies of human POFUT1 bound to GDP-fucose provide a roadmap for designing small-molecule inhibitors .
Product Specs
Product Science Overview
Protein O-Fucosyltransferase 1 (POFUT1) is an enzyme that plays a crucial role in the post-translational modification of proteins. It specifically catalyzes the transfer of fucose, a sugar molecule, to serine or threonine residues on target proteins. This modification is known as O-fucosylation and is essential for the proper functioning of several proteins, including those involved in Notch signaling pathways .
POFUT1 is a type II membrane protein located in the endoplasmic reticulum. It has a short N-terminal cytoplasmic domain, a single transmembrane domain, and a large C-terminal catalytic domain that faces the lumen of the endoplasmic reticulum . The enzyme recognizes specific consensus sequences on target proteins and attaches fucose to them, which can further be modified by other enzymes to form more complex glycan structures .
O-fucosylation mediated by POFUT1 is critical for the proper functioning of the Notch signaling pathway, which is involved in cell differentiation, proliferation, and apoptosis. Notch receptors, which are modified by POFUT1, interact with ligands to initiate signaling cascades that regulate gene expression . Disruptions in O-fucosylation can lead to various developmental disorders and diseases, including cancer .
Recombinant human POFUT1 is produced using advanced biotechnological methods. Typically, the gene encoding POFUT1 is cloned into an expression vector and introduced into a suitable host cell line, such as a mouse myeloma cell line (NS0). The host cells are cultured under conditions that promote the expression of the recombinant protein, which is then purified using techniques like affinity chromatography .
