Mesencephalic astrocyte-derived neurotrophic factor (MANF), Arginine-rich, mutated in early-stage tumors (ARMET), or arginine-rich protein (ARP) 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 ''MANF''

housekeeping gene In molecular biology, housekeeping genes are typically constitutive genes that are required for the maintenance of basic cellular function, and are expressed in all cells of an organism under normal and patho-physiological conditions. Although ...

. This gene encodes a highly conserved protein whose function is known. The protein was initially thought to be longer at the

N-terminus The N-terminus (also known as the amino-terminus, NH2-terminus, N-terminal end or amine-terminus) is the start of a protein or polypeptide, referring to the free amine group (-NH2) located at the end of a polypeptide. Within a peptide, the amin ...

and to contain an

arginine Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidinium, guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) a ...

-rich region but transcribed evidence indicates a smaller

open reading frame In molecular biology, reading frames are defined as spans of DNA sequence between the start and stop codons. Usually, this is considered within a studied region of a prokaryotic DNA sequence, where only one of the six possible reading frames ...

that does not encode the arginine tract. The presence of a specific mutation changing the previously numbered

codon Genetic code is a set of rules used by living cells to translate information encoded within genetic material (DNA or RNA sequences of nucleotide triplets or codons) into proteins. Translation is accomplished by the ribosome, which links prote ...

50 from ATG to AGG, or deletion of that codon, has been reported in a variety of solid tumors. With the protein size correction, this codon is now identified as the initiation codon. MANF has cytoprotective effects in neurons and pancreatic β cells, both in vitro (cell culture) and in vivo (animal models of neurodegeneration and diabetes). Specifically, it protects dopamine neurons from

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 ...

(ER) stress-induced death. It exerts this action by binding to

ERN1 The serine/threonine-protein kinase/endoribonuclease inositol-requiring enzyme 1 α (IRE1α) is an enzyme that in humans is encoded by the ''ERN1'' gene. Function The protein encoded by this gene is the ER to nucleus signalling 1 protein, a hu ...

, the

unfolded protein response The unfolded protein response (UPR) is a cellular stress response related to the endoplasmic reticulum (ER) stress. It has been found to be conserved between mammalian species, as well as yeast and worm organisms. The UPR is activated in response t ...

(UPR) sensor in the ER, which results in the attenuation of UPR.

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Further reading