During the asexual blood stage, binds to a chymotrypsin sensitive, neuraminidase and trypsin resistant receptor on the surface of the host erythrocyte (PubMed:21628513). Despite its binding capacity, appears to be dispensable for merozoite invasion of host erythrocytes (PubMed:12606570, PubMed:21698217). During the asexual blood stage, binds to a trypsin-resistant and chymotrypsin and neuraminidase sensitive receptor on the surface of the host erythrocyte. Forms a heterodimer composed of the 285 kDa and the 85 kDa forms. Localizes to the rhoptry neck at the apical end of the merozoite (PubMed:21628513, PubMed:12228308). 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 (PubMed:21628513). Also, the different processed forms are released from the membrane following proteolytic cleavage (PubMed:21628513). 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. 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. Expressed during parasite asexual blood stages, specifically at the late schizont stage prior to merozoite release and in free merozoites (at protein level). Proteolytically processed into multiple fragments following schizont rupture (PubMed:21628513, PubMed:12228308, PubMed:21698217). In the mature schizont stage prior to merozoite release, full length RH2b is processed post-Golgi into C-terminal 285 kDa and N-terminal 85 kDa forms (PubMed:21628513, PubMed:21698217). During merozoite invasion of host erythrocytes, further processing occurs generating a 140 kDa C-terminal form (PubMed:21628513). At the same time, the C-terminal transmembrane region is probably cleaved, probably by a rhomboid protease, to shed all the different processed protein forms from the membrane leaving a transmembrane 7 kDa form on the merozoite surface (PubMed:21628513, PubMed:21698217). Does not affect merozoite invasion of host erythrocytes, either untreated or treated with neuraminidase, trypsin or chymotrypsin. Possible candidate for an effective malaria vaccine as determined by epitope response in sera. 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 (PubMed:12228308, PubMed:12606570). A similar variation in expression affects other reticulocyte-binding proteins such as RH2b and RH1 (PubMed:12228308, PubMed:12606570). 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).