Engulfment and cell motility protein 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 ''ELMO1''
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 ...
.
ELMO1 is located on chromosome number seven in humans and is located on chromosome number thirteen in mice.
Structure
The human engulfment and cell motility protein 1, ELMO1, is 720 residues in length. The protein contains the following three domains:
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N-terminal
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 ...
Armadillo
Armadillos () are New World placental mammals in the order (biology), order Cingulata. They form part of the superorder Xenarthra, along with the anteaters and sloths. 21 extant species of armadillo have been described, some of which are dis ...
domain (residues 82-262)
* central
ELMO
Elmo is a Muppet character on the children's television show ''Sesame Street''. A furry red monster who speaks in a high-pitched falsetto voice and frequently refers to himself in the third person, he hosts the last full 15-minute segmen ...
(
Engulfment and Cel
l Motility) domain (301-492)
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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 ...
pleckstrin homology 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 ...
(residues 527-674)
ELMO1 also has a pro-rich motif at the extreme C terminus. Secondary structure analysis has predicted that there are alpha-helical regions at both the N and C-terminus.
[; ]
The structure of the pleckstrin homology domain of ELMO1 has been determine by X-ray crystallography.
Function
The protein encoded by this gene interacts with the dedicator of cyto-kinesis 1 protein to promote phagocytosis and effect cell shape changes. Similarity to a C. elegans protein suggests that this protein may function in apoptosis and in cell migration. Alternative splicing of this gene results in multiple transcript variants encoding different isoforms.
Interactions
ELMO1 has been shown to
interact
Advocates for Informed Choice, dba interACT or interACT Advocates for Intersex Youth, is a 501(c)(3) nonprofit organization advocating for the legal and human rights of children with intersex traits. The organization was founded in 2006 and fo ...
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 ...
and
HCK. ELMO1 directly interacts with the SH3 domain of HCK. The association between ELMO1 and HCK is dependent on polyproline interactions.
When ELMO1 is complexed with DOCK180,
Rac GTPase-dependent biological processes are activated. The pH domain of ELMO1 functions in trans to stabilize DOCK180 and make it resistant to degradation. When ELMO1 binds to DOCK180 it relieves the steric inhibition of DOCK180 which then activates the Rac GTPase. The pro-rich motif of the C terminus on ELMO1 is essential for the binding of ELMO1 to the SH3 domain at the N terminus of DOCK180.
The complex of ELMO1 and DOCK180 act as a regulator of Rac during development of a cell and cell migration. Mutation of both interaction sites for DOCK180 on ELMO1 will lead to the disruption of the ELMO1-DOCK180 complex. ELMO1 complexed with both DOCK180 and CrkII leads to maximal efficiency of
phagocytosis
Phagocytosis () is the process by which a cell (biology), cell uses its plasma membrane to engulf a large particle (≥ 0.5 μm), giving rise to an internal compartment called the phagosome. It is one type of endocytosis. A cell that performs ph ...
in the cell. This complex of molecules happens upstream of Rac during phagocytosis.
References
Further reading
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