EGF-like domain
{{short description|Protein domain named after the epidermal growth factor protein}}
{{missing information|consensus cystine repeat, difulfide bond position (residues, inter/intra?)|date=March 2019}}
{{Infobox protein family
| Symbol = EGF
| Name = EGF-like domain
| image = PDB 1hre EBI.jpg
| width =
| caption = Structure of the epidermal growth factor-like domain of heregulin-alpha.{{cite journal |vauthors=Nagata K, Kohda D, Hatanaka H |title=Solution structure of the epidermal growth factor-like domain of heregulin-alpha, a ligand for p180erbB-4 |journal=EMBO J. |volume=13 |issue=15 |pages=3517–23 |date=August 1994 |pmid=8062828 |pmc=395255 |doi= 10.1002/j.1460-2075.1994.tb06658.x|display-authors=etal}}
| Pfam= PF00008
| Pfam_clan= CL0001
| ECOD = 389.1.1
| InterPro= IPR000742
| SMART=
| PROSITE = PDOC00021
| SCOP = 1apo
| TCDB =
| OPM family=
| OPM protein=
| CDD = cd00053
| PDB=
}}
{{Infobox protein family
| Symbol = EGF_2
| Name = EGF-like domain, extracellular
| image = PDB 1jv2 EBI.jpg
| width =
| caption = crystal structure of the extracellular segment of integrin alphavbeta3
| Pfam = PF07974
| Pfam_clan = CL0001
| InterPro = IPR013111
| SMART =
| PROSITE =
| MEROPS =
| SCOP =
| TCDB =
| OPM family =
| OPM protein =
| CAZy =
| CDD = cd00054
}}
The EGF-like domain is an evolutionary conserved protein domain, which derives its name from the epidermal growth factor where it was first described. It comprises about 30 to 40 amino-acid residues and has been found in a large number of mostly animal proteins.{{cite journal |vauthors=Downing AK, Knott V, Werner JM, Cardy CM, Campbell ID, Handford PA | title = Solution structure of a pair of calcium-binding epidermal growth factor-like domains: implications for the Marfan syndrome and other genetic disorders | journal = Cell | volume = 85 | issue = 4 | pages = 597–605 |date=May 1996 | pmid = 8653794 | doi = 10.1016/S0092-8674(00)81259-3| s2cid = 15410014 | doi-access = free }}{{cite journal |vauthors=Bork P, Downing AK, Kieffer B, Campbell ID | title = Structure and distribution of modules in extracellular proteins | journal = Q. Rev. Biophys. | volume = 29 | issue = 2 | pages = 119–67 |date=May 1996 | pmid = 8870072 | doi = 10.1017/S0033583500005783| s2cid = 6104446 }} Most occurrences of the EGF-like domain are found in the extracellular domain of membrane-bound proteins or in proteins known to be secreted. An exception to this is the prostaglandin-endoperoxide synthase. The EGF-like domain includes 6 cysteine residues which in the epidermal growth factor have been shown to form 3 disulfide bonds. The structures of 4-disulfide EGF-domains have been solved from the laminin and integrin proteins. The main structure of EGF-like domains is a two-stranded β-sheet followed by a loop to a short C-terminal, two-stranded β-sheet. These two β-sheets are usually denoted as the major (N-terminal) and minor (C-terminal) sheets.{{cite journal |vauthors=Wouters MA, Rigoutsos I, Chu CK, Feng LL, Sparrow DB, Dunwoodie SL | title = Evolution of distinct EGF domains with specific functions | journal = Protein Science | volume = 14 | issue = 4 | pages = 1091–103| year = 2005 | pmid = 15772310| doi = 10.1110/ps.041207005 | pmc=2253431}} EGF-like domains frequently occur in numerous tandem copies in proteins: these repeats typically fold together to form a single, linear solenoid domain block as a functional unit.
Subtypes
Two main subtypes of EGF-like domains have been identified:{{cite journal |vauthors=Bersch B, Hernandez JF, Marion D, Arlaud GJ | title = Solution Structure of the Epidermal Growth Factor (EGF)-like Module of Human Complement Protease C1r, an Atypical Member of the EGF Family | journal = Biochemistry | volume = 37 | issue = 5 | pages = 1204–14| year = 1998 | pmid = 9477945| doi = 10.1021/bi971851v}} The human EGF-like (hEGF) domain and the complement C1r-like (cEGF) domain. The latter occurs as two subtypes, 1 and 2, whereas there is only a single hEGF-like domain subtype. Both the hEGF- and cEGF-like domains contain three disulfides and derive from a common ancestor that carried four disulfides, of which one was lost during evolution. The lost cysteines of the common ancestor differ between cEGF- and hEGF-like domains and hence these types differ in their disulfide linkages. The differentiation of cEGF into subtype 1 and 2, which probably occurred after its split from hEGF, is based on different residue numbers between the distinct half-cystines. Both hEGF- and cEGF-like domains contain an N-terminal calcium binding region.
Both subtypes display unusual post-translational modifications, including O-glycosylations and β-hydroxylation of aspartate and asparagine residues. O-fucose modifications have only been detected in hEGF-like domains and they are important for the proper folding of the hEGF-like domain. β-Hydroxylation appears in hEGF- and cEGF-like domains, the former is hydroxylated on an aspartic acid while the latter is hydroxylated on an asparagine residue. The biological role of this post-translational modification is unclear.
Either or both subtypes may be found in proteins containing EGF-like domains. In many mitogenic and developmental proteins such as Notch and Delta the EGF-like domains are only of the hEGF type. Other proteins contain only cEGF such as thrombomodulin and the LDL-receptor. In mixed EGF-proteins the hEGF- and cEGF-like domains are grouped together with the hEGFs always being N-terminal of the cEGFs. Such proteins are involved in blood coagulation or are components of the extracellular matrix like fibrillin and LTBP-1 (Latent-transforming growth factor beta-binding protein 1). In addition to the aforementioned three disulfide hEGF- and cEGF-like types, there are proteins carrying a four-disulfide EGF-like domain like laminin and integrins.
Role in the immune system and apoptosis
Selectins, a group of proteins that are involved in leukocyte rolling towards a source of inflammation, contain an EGF-like domain along with a lectin domain and short consensus repeats (SCRs).{{cite journal |vauthors=Kansas GS, Saunders KB, Ley K | title = A role for the epidermal growth factor-like domain of P-selectin in ligand recognition and cell adhesion | journal = J Cell Biol | volume = 124 | issue = 4 | pages = 609–18| year = 1994 | pmid = 7508943 | pmc=2119911 | doi=10.1083/jcb.124.4.609|display-authors=etal}}{{cite journal |vauthors=Phan UT, Waldron TT, Springer TA | title = Remodeling of the lectin-EGF-like domain interface in P- and L-selectin increases adhesiveness and shear resistance under hydrodynamic force | journal = Nat Immunol | volume = 7 | issue = 8 | pages = 883–9| year = 2006 | pmid = 16845394 | doi = 10.1038/ni1366 | pmc=1764822}} The functions of the EGF-like domain vary between different selectin types. For example, EGF-like domains appear essential to ligand binding by P-selectin but not L-selectin, and are thus essential to the proper adhesive function of platelets. Additionally, immature human dendritic cells appear to require interactions with the EGF-like domains of selectins during their maturation process.{{cite journal |vauthors=Zhou T, Zhang Y, Sun G | title = Anti-P-selectin lectin-EGF domain monoclonal antibody inhibits the maturation of human immature dendritic cells. | journal = Exp Mol Pathol | volume = 80 | issue = 2 | pages = 171–6| year = 2006 | pmid =16413535 | doi = 10.1016/j.yexmp.2005.10.004 |display-authors=etal}}
The EGF-like domain is also part of laminins, an important group of extracellular proteins. The EGF-like domains are usually masked in intact membranes, but become exposed when the membrane is destroyed, e.g. during inflammation, thereby stimulating membrane growth and restoring damaged membrane parts.{{cite book| last1=Löffler |first1=G |last2=Petrides |first2= PE |last3= Heinrich |first3= PC |year=1997|title= Biochemie und Pathobiochemie |edition=5th |publisher= Springer-Verlag |location=Berlin, Heidelberg |isbn=3-540-59006-4 |pages= 747}} During apoptosis, the EGF-like domain repeats of stabilin-2 recognize and bind apoptotic cells, probably by recognizing phosphatidylserine, an apoptotic cell marker.{{cite journal |vauthors=Park SY, Kim SY, Jung MY | title = Epidermal growth factor-like domain repeat of stabilin-2 recognizes phosphatidylserine during cell corpse clearance.| journal = Mol Cell Biol | volume = 28 | issue = 17 | pages = 5288–98| year = 2008 | pmid =18573870 | doi=10.1128/MCB.01993-07 | pmc=2519725|display-authors=etal}}
Calcium binding
Calcium-binding EGF-like domains (cbEGF-like domains) play a central role in diseases such as Marfan syndrome{{cite journal |vauthors=Handford PA, Downing AK, Rao Z, Hewett DR, Sykes BC, Kielty CM | title = The calcium binding properties and molecular organization of epidermal growth factor-like domains in human fibrillin-1.| journal = J. Biol. Chem. | volume = 270 | issue = 12 | pages = 6751–6 | year = 1991 | pmid = 7896820 | doi=10.1074/jbc.270.12.6751| doi-access = free }} or the X-chromosome linked hemorrhagic disorder hemophilia B{{cite journal |vauthors=Handford PA, Mayhew M, Baron M, Winship PR, Campbell ID, Brownlee GG | title = Key residues involved in calcium-binding motifs in EGF-like domains.| journal = Nature | volume = 351 | issue = 6322| pages = 164–7| year = 1991 | pmid = 2030732 | doi=10.1038/351164a0| bibcode = 1991Natur.351..164H| s2cid = 4338236}} and are among the most abundant extracellular calcium-binding domains.{{cite journal |vauthors=Stenflo J, Stenberg Y, Muranyi A | title = Calcium-binding EGF-like modules in coagulation proteinases: function of the calcium ion in module interactions | journal = Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology | volume = 1477| issue = 1–2| pages = 51–63| year = 2000 | pmid = 10708848 | doi=10.1016/s0167-4838(99)00262-9}} cbEGF- like domains impart specific functions to a variety of proteins in the blood clotting cascade, including coagulation factors VII, IX and X, protein C, and its cofactor protein S.
Calcium-binding EGF-like domains are typically composed of 45 amino acids, arranged as two antiparallel beta sheets. Several cysteine residues within this sequence form disulfide bridges. These domains show no significant structural deviations from other EGF-like domains, but can bind a single calcium ion via a consensus Asp-Leu/Ile-Asp-Gln-Cys motif. The binding affinity to calcium varies widely and often depends on adjacent domains. Calcium binding has been found to be associated with induction of unusual posttranslational modifications of cbEGF-like domains in proteins such as fibrillin-1.{{cite journal |vauthors=Glanville RW, Qian RQ, McClure DW, Maslen CL | title = Calcium binding, hydroxylation, and glycosylation of the precursor epidermal growth factor-like domains of fibrillin-1, the Marfan gene protein.| journal = J. Biol. Chem. | volume = 269 | issue = 43 | pages = 26630–4| year = 1994 | doi = 10.1016/S0021-9258(18)47065-2| pmid = 7929395|display-authors=etal| doi-access = free}}
Multiple cbEGF domains are often connected by one or two amino acids to form larger, repetitive arrays, referred to as 'cbEGF modules'. These modules may contain from 2 to 43 individual cbEGF domains.{{cite journal |vauthors=Piha-Gossack A, Sossin W, Reinhardt DT | title = The evolution of extracellular fibrillins and their functional domains | journal = PLOS ONE | volume = 7| issue = 3| pages = 33560| year = 2012 | pmid = 22438950 | doi=10.1371/journal.pone.0033560 | pmc=3306419| bibcode = 2012PLoSO...733560P |display-authors=etal| doi-access = free }} cbEGF modules exhibit altered calcium-binding affinity (compared to the isolated domains) and also are involved in regulation of other domains of the protein.{{cite journal |vauthors=Sunnerhagen M, Olah GA, Stenflo J, Forsen S, Drakenberg T, Trewhella J | title = The relative orientation of Gla and EGF domains in coagulation factor X is altered by Ca2+ binding to the first EGF domain. A combined NMR-small angle X-ray scattering study | journal = Biochemistry | volume = 35| issue = 36| pages = 11547–59| year = 1996 | pmid = 8794734 | doi=10.1021/bi960633j}}
Mutant cbEGF-like domains with impaired calcium binding underlie some genetic disorders. For example, point mutations causing defective calcium binding to coagulation factor IX underlies some forms of hemophilia B, and mutations that prevent proper interactions between cbEGF domains in this protein may further complicate this disorder.
Proteins containing this domain
Below is a list of human proteins containing the EGF-like domain:
- AGC1; AGRIN; AREG; ATRN; ATRNL1;
- BCAN; BMP1; BTC;
- C1S; CASPR4; CD248; CD93; CELSR1; CELSR2; CELSR3; CLEC14A; CNTNAP1; CNTNAP2; CNTNAP3; CNTNAP4; CNTNAP5; COMP; COX-2; CRB1; CRB2; CSPG3; CUBN;
- DLK1; DLL1; DLL3; DLL4; DNER;
- EDIL3; EGF; EGFL11; EGFL8; EGFL9; EGFLAM; EPGN; EREG;
- F7; F9; F10; F12; FAT; FAT2; FAT4; FBN1; FBN2; FBN3;
- GAS6;
- HABP2; HBEGF; HEG1; HGFAC; HMCN1; HSPG2;
- ITGB5;
- JAG1; JAG2;
- LDLR; LRP1; LRP10; LRP1B; LRP2; LRP4; LRP5; LRP6; LRP8; LTBP1; LTBP2; LTBP3; LTBP4;
- MATN1; MATN2; MATN3; MATN4; MEGF12; MEGF6; MEP1A; MEP1B; MFGE8; MMRN1; MMRN1; MUC4;
- NAGPA; NID1; NID2; NOTCH1; NOTCH2; NOTCH2NL; NOTCH3; NOTCH4; NRG1; NRG2; NRG3; NRG4; NRXN1; NRXN2; NRXN3; NTNG2;
- ODZ1; ODZ2; OIT3;
- PLAT; PP187; PROC; PROS1; PROZ; PTGS1; PTGS2;
- RAMP;
- SCUBE1; SCUBE2; SCUBE3; SEL-OB; SELE; SELL; SELP; SLIT1; SLIT2; SLIT3; SNED1; STAB1; STAB2; SVEP1;
- TECTA; TGFA; THBD; THBS1; THBS2; THBS4; TIE1; TLL1; TLL2; TMEFF1; TMEFF2; TNC; TNXB;
- UMOD;
- VASN; VCAN; VLDLR; VWA2;
- WIF1;
- ZAN;