Sema domain

Pfam_box
Symbol = Sema
Name =


width =250
caption =Sema domain, immunoglobulin domain (Ig), short basic domain
Pfam= PF01403
InterPro= IPR001627
SMART=
PROSITE = PDOC51004
SCOP = 1olz
TCDB =
OPM family=
OPM protein=
PDB=PDB3|1shyB:55-500 PDB3|1ux3A:55-500 PDB3|1olzA:50-482PDB3|1q47A:57-498

The Sema domain is a structural domain of semaphorins, which are a large family of secreted and transmembrane proteins, some of which function as repellent signals during axon guidance. Sema domains also occur in UniProt|P08581 the hepatocyte growth factor receptor and UniProt|P51805 cite journal |author=Goodman CS, Winberg ML, Noordermeer JN, Tamagnone L, Comoglio PM, Spriggs MK, Tessier-Lavigne M |title=Plexin A is a neuronal semaphorin receptor that controls axon guidance |journal=Cell |volume=95 |issue=7 |pages=903–916 |year=1998 |pmid=9875845 |doi=10.1016/S0092-8674(00)81715-8] and in viral proteins.

CD100 (also called SEMA4D) is associated with PTPase and serine kinase activity. CD100 increases PMA, CD3 and CD2 induced T cell proliferation, increases CD45 induced T cell adhesion, induces B cell homotypic adhesion and down-regulates B cell expression of CD23.

The Sema domain is characterised by a conserved set of cysteine residues, which form four disulfide bonds to stabilise the structure. The Sema domain fold is a variation of the beta propeller topology, with seven blades radiallyarranged around a central axis. Each blade contains a four- stranded (strands A to D) antiparallel beta sheet. The inner strand of each blade (A) lines the channel at the centre of the propeller, with strands B and C of the same repeat radiating outward, and strand D of the next repeat forming the outer edge of the blade. The large size of the Sema domain is not due to a single inserted domain but results from the presence of additional secondary structure elements inserted in most of the blades. The Sema domain uses a 'loop and hook' system to close the circle between the first and the last blades. The blades are constructed sequentially with an N-terminal beta- strand closing the circle by providing the outermost strand (D) of the seventh (C-terminal) blade. The beta-propeller is further stabilized by an extension of the N-terminus, providing an additional, fifth beta-strand on the outer edge of blade 6cite journal |author=Nikolov DB, Himanen JP, Rajashankar KR, Lu M, Antipenko A, Lesniak J, Barton WA, Hoemme C, Puschel AW, van Leyen K, Nardi-Dei V |title=Structure of the semaphorin-3A receptor binding module |journal=Neuron |volume=39 |issue=4 |pages=589–598 |year=2003 |pmid=12925274 |doi=10.1016/S0896-6273(03)00502-6] cite journal |author=Stuart DI, Jones EY, Harlos K, Esnouf RM, Davis SJ, Love CA, Mavaddat N |title=The ligand-binding face of the semaphorins revealed by the high-resolution crystal structure of SEMA4D |journal=Nat. Struct. Biol. |volume=10 |issue=10 |pages=843–848 |year=2003 |pmid=12958590 |doi=10.1038/nsb977] cite journal |author=Lazarus RA, Kirchhofer D, Stamos J, Yao X, Wiesmann C |title=Crystal structure of the HGF beta-chain in complexwith the Sema domain of the Met receptor |journal=EMBO J. |volume=23 |issue=12 |pages=2325–2335 |year=2004 |pmid=15167892 |doi=10.1038/sj.emboj.7600243] .

CD molecules are leucocyte antigens on cell surfaces. CD antigens nomenclature is updated at Protein Reviews On The Web (http://mpr.nci.nih.gov/prow/).

Human proteins containing this domain

MET; MST1R; PLXNA1; PLXNA2; PLXNA3; PLXNA4; PLXNB1; PLXNB2;
PLXNB3; PLXND1; SEMA3A; SEMA3B; SEMA3C; SEMA3D; SEMA3E; SEMA3F;
SEMA3G; SEMA4A; SEMA4B; SEMA4C; SEMA4D; SEMA4F; SEMA4G; SEMA5A;
SEMA5B; SEMA6A; SEMA6B; SEMA6C; SEMA6D; SEMA7A;

References