Immunity-related GTPase family M protein (IRGM), also known as interferon-inducible protein 1 (IFI1), is an
enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ...
that in humans is ''IRGM''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
IRGM is a member of the
interferon-inducible GTPase family. The encoded protein may play a role in the
innate immune response
The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the ...
by regulating
autophagy
Autophagy (or autophagocytosis; from the Ancient Greek , , meaning "self-devouring" and , , meaning "hollow") is the natural, conserved degradation of the cell that removes unnecessary or dysfunctional components through a lysosome-dependent re ...
formation in response to intracellular pathogens.
The gene has been disabled by an
Alu element
An Alu element is a short stretch of DNA originally characterized by the action of the ''Arthrobacter luteus (Alu)'' restriction endonuclease. ''Alu'' elements are the most abundant transposable elements, containing over one million copies disp ...
for at least 25 million years in the
primate
Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...
lineage leading to
great ape
The Hominidae (), whose members are known as the great apes or hominids (), are a taxonomic family of primates that includes eight extant species in four genera: '' Pongo'' (the Bornean, Sumatran and Tapanuli orangutan); ''Gorilla'' (the east ...
s including humans, but it was re-enabled by an
endogenous retrovirus
Endogenous retroviruses (ERVs) are endogenous viral elements in the genome that closely resemble and can be derived from retroviruses. They are abundant in the genomes of jawed vertebrates, and they comprise up to 5–8% of the human genome (l ...
called ERV-9.
Clinical relevance
Polymorphisms that affect the normal expression of this gene are associated with a susceptibility to