The following text describes a protein:
Function:
[Reticulocyte-binding protein homolog 2a]: During the asexual blood stage, binds to a chymotrypsin sensitive, neuraminidase and trypsin resistant receptor on the surface of the host erythrocyte. Despite its binding capacity, appears to be dispensable for merozoite invasion of host erythrocytes; [Reticulocyte-binding protein homolog 2a 85 kDa form]: During the asexual blood stage, binds to a trypsin-resistant and chymotrypsin and neuraminidase sensitive receptor on the surface of the host erythrocyte.
Miscellaneous:
MISCELLANEOUS: RH2a expression levels greatly vary between isolates; levels are high in isolates 3D7, T996, HB3, D10, 7G8, K1, Pf120 and W2mef, and undetectable in isolates MCAMP, FCB1, T994 and FCR3. A similar variation in expression affects other reticulocyte-binding proteins such as RH2b and RH1. The expression pattern of RH1, RH2a and RH2b allows the strain to use different invasion pathways to enter erythrocytes (Probable). This provides a mechanism of phenotypic variation to evade host immune responses and to adapt to the polymorphic nature of the erythrocyte receptors in human populations (Probable).
Subcellular Localization:
Cell membrane; Single-pass type I membrane protein. Cytoplasmic vesicle, secretory vesicle, rhoptry. Secreted. Cell junction, tight junction. Note=Localizes to the rhoptry neck at the apical end of the merozoite. During merozoite invasion, mainly localizes to the tight junction formed between the parasite and the host erythrocyte membranes and then moves with the tight junction to the posterior end as the parasite enters the erythrocyte. Also, the different processed forms are released from the membrane following proteolytic cleavage; [Reticulocyte-binding protein homolog 2a 85 kDa form]: Secreted. Cell membrane; Peripheral membrane protein; Extracellular side. Note=In mature schizont, co-localizes to the apical end of the schizont and the merozoite with reticulocyte-binding protein homolog 2b 285 kDa form. During merozoite invasion, shed from the cell surface; [Reticulocyte-binding protein homolog 2a 285 kDa form]: Secreted. Cell membrane; Single-pass type I membrane protein. Note=In mature schizont, co-localizes to the apical end of the schizont and the merozoite with reticulocyte-binding protein homolog 2b 85 kDa form. During merozoite invasion, shed from the cell surface.
Sequence:
MKTTLFCSISFCNIIFFFLELSHEHFVGQSSNTHGASSVTDFNFSEEKNLKSFEGKNNNNDNYASINRLYRKKPYMKRSLINLENDLFRLEPISYIQRYYKKNINRSDIFHNKKERGSKVYSNVSSFHSFIQEGKEEVEVFSIWGSNSVLDHIDVLRDNGTVVFSVQPYYLDIYTCKEAILFTTSFYKDLDKSSITKINEDIEKFNEEIIKNEEQCLVGGKTDFDNLLIVLENAEKANVRKTLFDNTFNDYKNKKSSFYNCLKNKKNDYDKKIKNIKNEITKLLKNIESTGNMCKTESYVMNNNLYLLRVNEVKSTPIDLYLNRAKELLESSSKLVNPIKMKLGDNKNMYSIGYIHDEIKDIIKRYNFHLKHIEKGKEYIKRITQANNIADKMKKDELIKKIFESSKHFASFKYSNEMISKLDSLFIKNEEILNNLFNNIFNIFKKKYETYVDMKTIESKYTTVMTLSEHLLEYAMDVLKANPQKPIDPKANLDSEVVKLQIKINEKSNELDNAISQVKTLIIIMKSFYDIIISEKASMDEMEKKELSLNNYIEKTDYILQTYNIFKSKSNIINNNSKNISSKYITIEGLKNDIDELNSLISYFKDSQETLIKDDELKKNMKTDYLNNVKYIEENVTHINEIILLKDSITQRIADIDELNSLNLININDFINEKNISQEKVSYNLNKLYKGSFEELESELSHFLDTKYLFHEKKSVNELQTILNTSNNECAKLNFMKSDNNNNNNNSNIINLLKTELSHLLSLKENIIKKLLNHIEQNIQNSSNKYTITYTDINNRMEDYKEEIESLEVYKHTIGNIQKEYILHLYENDKNALAVHNTSMQILQYKDAIQNIKNKISDDIKILKKYKEMNQDLLNYYEILDKKLKDNTYIKEMHTASLVQITQYIPYEDKTISELEQEFNNNNQKLDNILQDINAMNLNINILQTLNIGINACNTNNKNVEHLLNKKIELKNILNDQMKIIKNDDIIQDNEKENFSNVLKKEEEKLEKELDDIKFNNLKMDIHKLLNSYDHTKQNIESNLKINLDSFEKEKDSWVHFKSTIDSLYVEYNICNQKTHNTIKQQKNDIIELIYKRIKDINQEIIEKVDNYYSLSDKALTKLKSIHFNIDKEKYKNPKSQENIKLLEDRVMILEKKIKEDKDALIQIKNLSHDHFVNADNEKKKQKEKEEDDEQTHYSKKRKVMGDIYKDIKKNLDELNNKNLIDITLNEANKIESEYEKILIDDICEQITNEAKKSDTIKEKIESYKKDIDYVDVDVSKTRNDHHLNGDKIHDSFFYEDTLNYKAYFDKLKDLYENINKLTNESNGLKSDAHNNNTQVDKLKEINLQVFSNLGNIIKYVEKLENTLHELKDMYEFLETIDINKILKSIHNSMKKSEEYSNETKKIFEQSVNITNQFIEDVEILKTSINPNYESLNDDQIDDNIKSLVLKKEEISEKRKQVNKYITDIESNKEQSDLHLRYASRSIYVIDLFIKHEIINPSDGKNFDIIKVKEMINKTKQVSNEAMEYANKMDEKNKDIIKIENELYNLINNNIRSLKGVKYEKVRKQARNAIDDINNIHSNIKTILTKSKERLDEIKKQPNIKREGDVLNNDKTKIAYITIQINNGRIESNLLNILNMKHNIDTILNKAMDYMNDVSKSDQIVINIDSLNMNDIYNKDKDLLINILKEKQNMEAEYKKMNEMYNYVNETEKEIIKHKKNYEIRIMEHIKKETNEKKKKFMESNNKSLTTLMDSFRSMFYNEYINDYNINENFEKHQNILNEIYNGFNESYNIINTKMTEIINDNLDYNEIKEIKEVAQTEYDKLNKKVDELKNYLNNIKEQEGHRLIDYIKEKIFNLYIKCSEQQNIIDDSYNYITVKKQYIKTIEDVKFLLDSLNTIEEKNKSVANLEICTNKEDIKNLLKHVIKLANFSGIIVMSDTNTEITPENPLEDNDLLNLQLYFERKHEITSTLENDSDLELDHLGSNSDESIDNLKVYNDIIELHTYSTQILKYLDNIQKLKGDCNDLVKDCKELRELSTALYDLKIQITSVINRENDISNNIDIVSNKLNEIDAIQYNFEKYKEIFDNVEEYKTLDDTKNAYIVKKAEILKNVDINKTKEDLDIYFNDLDELEKSLTLSSNEMEIKTIVQNSYNSFSDINKNINDIDKEMKTLIPMLDELLNEGHNIDISLYNFIIRNIQIKIGNDIKNIREQENDTNICFEYIQNNYNFIKSDISIFNKYDDHIKVDNYISNNIDVVNKHNSLLSEHVINATNIIENIMTSIVEINEDTEMNSLEETQDKLLELYENFKKEKNIINNNYKIVHFNKLKEIENSLETYNSISTNFNKINETQNIDILKNEFNNIKTKINDKVKELVHVDSTLTLESIQTFNNLYGDLMSNIQDVYKYEDINNVELKKVKLYIENITNLLGRINTFIKELDKYQDENNGIDKYIEINKENNSYIIKLKEKANNLKENFSKLLQNIKRNETELYNINNIKDDIMNTGKSVNNIKQKFSSNLPLKEKLFQMEEMLLNINNIMNETKRISNTAAYTNITLQDIENNKNKENNNMNIETIDKLIDHIKIHNEKIQAEILIIDDAKRKVKEITDNINKAFNEITENYNNENNGVIKSAKNIVDEATYLNNELDKFLLKLNELLSHNNNDIKDLGDEKLILKEEEERKERERLEKAKQEEERKERERIEKEKQEKERLEREKQEQLKKEEELRKKEQERQEQQQKEEALKRQEQERLQKEEELKRQEQERLEREKQEQLQKEEELKRQEQERLQKEEALKRQEQERLQKEEELKRQEQERLEREKQEQLQKEEELKRQEQERLQKEEALKRQEQERLQKEEELKRQEQERLERKKIELAEREQHIKSKLESDMVKIIKDELTKEKDEIIKNKDIKLRHSLEQKWLKHLQNILSLKIDSLLNKNDEVIKDNETQLKTNILNSLKNQLYLNLKRELNEIIKEYEENQKKILHSNQLVNDSLEQKTNRLVDIKPTKHGDIYTNKLSDNETEMLITSKEKKDETESTKRSGTDHTNSSESTTDDNTNDRNFSRSKNLSVAIYTAGSVALCVLIFSSIGLLLIKTNSGDNNSNEINEAFEPNDDVLFKEKDEIIEITFNDNDSTI