Type:Protein
SpeciesReactivity:H;R
B=Bovine;Ca=Cat;Ch=Chicken;D=Dog;EQ=Equine;GP=GuineaPig;H=Human;M=Mouse;P=Porcine;Pr=Primate;R=Rat;Rb=Rabbit;Y=Yeast;Xe=Xenopus;Ze=Zebrafish;;;;NA-NotApplicable;STP=Step-TactinProteins;All
S100A13isan11kDamemberoftheS100(solublein100%saturatedammoniumsulfate)familyofvertebrateEFhandCa++bindingproteins(13).Itiswidelyexpressedasahomodimerwithtwo98aminoacid(aa)longsubunits(2,3).HumanS100A13shares83%,90%,91%,87%,78%and47%aaidentitywithmouse,rat,cow,dog,opossumandchickenS100A13,respectively.LikeotherS100proteins,S100A13issmallandgenerallyacidic,butcontainsabasicresiduerichsequenceattheC-terminus,andtwoEFhandmotifsthatbindwithCa++differingaffinities(24).SomeS100proteins,includingS100A13,areabletobindthecellsurfacereceptorforadvancedglycationendproducts(RAGE)(5).
Image:S100A13-InducedNeuriteOutgrowth.RecombinanthumanS100A13immobilizedonanitrocellulose-coatedmicroplate.
Despitelackingasignalsequence,S100A13playsanimportantroleinCu++dependentexportofFGF1(FGFacidic)andIL1αfromthecellinresponsetostressessuchasheatshock,anoxiaandstarvation(68).BindingofcopperisnecessaryforformationofamultiproteincomplexbetweenS100A13,FGF1andp40synaptotagmin1(syt1)(9,10).Cu++ionssuppliedbyS100A13arethoughttooxidizeanddownregulatetheactivityofFGF1priortoexport(10).CalciuminfluxmayalsoplayasimilarroleinFGF1releasefromneuronalcells(11).S100A13iscomposedoffouramphiphilichelicesthatmayinteractwithacidicphospholipidheadgroups.WithFGF1andsyt1,S100A13likelyperturbsthemembrane,whichallowstheS100A13proteincomplextoexitthecell(4,12).S100A13hasbeenproposedasaMarkerforangiogenesisintumorsandendometrium,duetoitsroleinstressinducedexportofFGF1(13,14).Basedoninhousestudies,S100A13hasalsobeenfoundtopromoteneuriteoutgrowthfromratcorticalembryonicneurons.
