ELMO (Engulfment and Cell Motility) is a family of related

proteins Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, re ...

(~82 kDa) involved in

intracellular This glossary of biology terms is a list of definitions of fundamental terms and concepts used in biology, the study of life and of living organisms. It is intended as introductory material for novices; for more specific and technical definitions ...

signalling A signal is both the process and the result of transmission of data over some media accomplished by embedding some variation. Signals are important in multiple subject fields including signal processing, information theory and biology. In ...

networks. These proteins have no intrinsic

catalytic Catalysis () is the increase in reaction rate, rate of a chemical reaction due to an added substance known as a catalyst (). Catalysts are not consumed by the reaction and remain unchanged after it. If the reaction is rapid and the catalyst ...

activity and instead function as

adaptors An adapter or adaptor is a device that converts attributes of one electrical device or system to those of an otherwise incompatible device or system. Some modify power or signal attributes, while others merely adapt the physical form of one con ...

which can regulate the activity of other proteins through their ability to mediate protein-protein interactions. This family contains members in all animals. In humans there are three

paralogous Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speci ...

isoform A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene and are the result of genetic differences. While many perform the same or similar biological roles, some isoforms have uniqu ...

s: *

ELMO1 Engulfment and cell motility protein 1 is a protein that in humans is encoded by the ''ELMO1'' gene. ELMO1 is located on chromosome number seven in humans and is located on chromosome number thirteen in mice. Structure The human engulfment an ...

* ELMO2 * ELMO3 The ELMO domain was first characterized in the CED-12 proteins of ''

Caenorhabditis elegans ''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a Hybrid word, blend of the Greek ''caeno-'' (recent), ''r ...

'' and ''

Drosophila melanogaster ''Drosophila melanogaster'' is a species of fly (an insect of the Order (biology), order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly" ...

'', which is a homolog to the ELMO protein found in

mammals A mammal () is a vertebrate animal of the class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three middle e ...

. This protein is involved in Rac-GTPase activation, apoptotic cell phagocytosis,

cell migration Cell migration is a central process in the development and maintenance of multicellular organisms. Tissue formation during embryogenesis, embryonic development, wound healing and immune system, immune responses all require the orchestrated movemen ...

, and cytoskeletal rearrangements.

Structure and function of ELMO proteins

The ELMO family are evolutionarily conserved

orthologs Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a spec ...

of the ''

C. elegans ''Caenorhabditis elegans'' () is a free-living transparent nematode about 1 mm in length that lives in temperate soil environments. It is the type species of its genus. The name is a blend of the Greek ''caeno-'' (recent), ''rhabditis'' ( ...

'' protein CED-12. All isoforms contain a series of

armadillo repeats An armadillo repeat is a characteristic, repetitive amino acid peptide sequence, sequence of about 42 residue (chemistry)#biochemistry, residues in length that is found in many proteins. Proteins that contain armadillo repeats typically contain sev ...

, which begin 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 extend around two thirds of the way along the protein, as well as a

C-terminal The C-terminus (also known as the carboxyl-terminus, carboxy-terminus, C-terminal tail, carboxy tail, C-terminal end, or COOH-terminus) is the end of an amino acid chain (protein or polypeptide), terminated by a free carboxyl group (-COOH). When t ...

proline Proline (symbol Pro or P) is an organic acid classed as a proteinogenic amino acid (used in the biosynthesis of proteins), although it does not contain the amino group but is rather a secondary amine. The secondary amine nitrogen is in the p ...

-rich motif and a central

PH domain Pleckstrin homology domain (PH domain) or (PHIP) is a protein domain of approximately 120 amino acids that occurs in a wide range of proteins involved in intracellular signaling or as constituents of the cytoskeleton. This domain can bind phosph ...

. They function as part of a

protein complex A protein complex or multiprotein complex is a group of two or more associated polypeptide chains. Protein complexes are distinct from multidomain enzymes, in which multiple active site, catalytic domains are found in a single polypeptide chain. ...

with

Dock180 Dedicator of cytokinesis protein 1 (Dock1), also (DOCK180), is a large (~180 kDa) protein encoded in the human by the ''DOCK1'' gene, involved in intracellular signalling networks. It is the mammalian ortholog of the ''C. elegans'' protein CED ...

-related proteins to form a bipartite

guanine nucleotide exchange factor Guanine nucleotide exchange factors (GEFs) are proteins or protein domains that activate monomeric GTPases by stimulating the release of guanosine diphosphate (GDP) to allow binding of guanosine triphosphate (GTP). A variety of unrelated structu ...

for

Rac RAC or Rac may refer to: Organizations * Radio Amateurs of Canada * RATCH-Australia Corporation, electricity generator * Refugee Action Collective (Victoria), Melbourne, Australia * Religious Action Center of Reform Judaism, US * Rent-A-Cent ...

(a member of the

Rho family The Rho family of GTPases is a family of small (~21 kDa) signaling G proteins, and is a subfamily of the Ras superfamily. The members of the Rho GTPase family have been shown to regulate many aspects of intracellular actin dynamics, and are found ...

of small

G proteins G proteins, also known as guanine nucleotide-binding proteins, are a family of proteins that act as molecular switches inside cells, and are involved in transmitting signals from a variety of stimuli outside a cell to its interior. Their ...

). The Dock180-ELMO interaction requires the ELMO PH domain and also involves binding of the ELMO proline-rich motif to the Dock180

SH3 domain The SRC Homology 3 Domain (or SH3 domain) is a small protein domain of about 60 amino acid residues. Initially, SH3 was described as a conserved sequence in the viral adaptor protein v-Crk. This domain is also present in the molecules of ph ...

References

Protein families {{protein-stub