Protein ERGIC-53 also known as ER-Golgi intermediate compartment 53 kDa protein or lectin mannose-binding 1 is a

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...

that in humans is encoded by the ''LMAN1''

gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...

Function

ERGIC-53 (also named LMAN1) is a type I integral

membrane protein Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Integral membrane proteins are a permanent part of a cell membrane ...

localized in the intermediate region (

ERGIC The endoplasmic-reticulum–Golgi intermediate compartment (ERGIC) is an organelle in eukaryotic cells. This compartment mediates transport between the endoplasmic reticulum (ER) and Golgi complex, facilitating the sorting of cargo. The cluster wa ...

) between the

endoplasmic reticulum The endoplasmic reticulum (ER) is a part of a transportation system of the eukaryote, eukaryotic cell, and has many other important functions such as protein folding. The word endoplasmic means "within the cytoplasm", and reticulum is Latin for ...

and the Golgi, presumably recycling between the two compartments. The protein is a

mannose Mannose is a sugar with the formula , which sometimes is abbreviated Man. It is one of the monomers of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylatio ...

-specific

lectin Lectins are carbohydrate-binding proteins that are highly specific for sugar Moiety (chemistry), groups that are part of other molecules, so cause agglutination (biology), agglutination of particular cells or precipitation of glycoconjugates an ...

and is a member of a novel family of plant lectin homologs in the

secretory pathway Secretion is the movement of material from one point to another, such as a secreted chemical substance from a cell (biology), cell or gland. In contrast, excretion is the removal of certain substances or waste products from a cell or organism. Th ...

of animal cells. Mutations in the gene are associated with a

coagulation Coagulation, also known as clotting, is the process by which blood changes from a liquid to a gel, forming a thrombus, blood clot. It results in hemostasis, the cessation of blood loss from a damaged vessel, followed by repair. The process of co ...

defect. Using positional cloning, the gene was identified as the disease gene leading to combined deficiency of factor V-factor VIII, a rare, autosomal recessive disorder in which both coagulation factors V and VIII are diminished.

MCFD2 Multiple coagulation factor deficiency protein 2 is a protein that in humans is encoded by the ''MCFD2'' gene In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nu ...

is the second gene that leads to combined deficiency of factor V-factor VIII. ERGIC-53 and MCFD2 form a protein complex and serve as a cargo receptor to transport FV and FVIII from the ER to the ERGIC and then the Golgi,as illustrated here.
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Clinical significance

LMAN1

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, ...

al inactivation is a frequent and early event potentially contributing to colorectal tumorigenesis.

Function

Clinical significance

References

Further reading