During the asexual blood stage, binds to a chymotrypsin sensitive, neuraminidase and trypsin resistant receptor on the surface of the host erythrocyte and thus is involved in merozoite invasion (PubMed:27438226, PubMed:12606570). The various processed forms have different binding affinities for the erythrocyte receptor; full length form binds with higher affinity followed by the 250 kDa form and finally the 300 kDa form while the 160 kDa form does not bind erythrocytes (PubMed:27438226). After merozoite attachment and reorientation, RH2b binding to its erythrocyte receptor triggers an increase in intracellular Ca(2+) within the parasite resulting in the release of microneme proteins such as EBA175 which in turn leads to the formation of the tight junction between parasite and host cell (PubMed:27438226). During the asexual blood stage, binds to a trypsin-resistant and chymotrypsin and neuraminidase sensitive receptor on the surface of the host erythrocyte and thus is involved in merozoite invasion. Forms a heterodimer composed of the 297 kDa and the 85 kDa forms (PubMed:21698217). Interacts (via YF motif) with aldolase FBPA (PubMed:22991428). Localizes to the rhoptry neck at the apical end of the merozoite (PubMed:27438226, 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:27438226). Also, the different processed forms are released from the membrane following proteolytic cleavage (PubMed:27438226). The remaining 7 kDa processed transmembrane fragment is incorporated into the newly formed ring stage (PubMed:21698217). In mature schizont, co-localizes to the apical end of the schizont and the merozoite with reticulocyte-binding protein homolog 2b 297 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:27438226, PubMed:12228308, PubMed:21698217). In the mature schizont stage prior to merozoite release, full length RH2b is processed post-Golgi into C-terminal 297 kDa and N-terminal 85 kDa forms (PubMed:21698217, PubMed:27438226). Alternatively, full length RH2b can also be processed into C-terminal 250 kDa and N-terminal 130 kDa forms (PubMed:27438226). During merozoite invasion of host erythrocytes, further processing occurs generating a 160 kDa form (PubMed:27438226). At the same time, the C-terminal transmembrane region is 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:27438226, PubMed:21698217). Phosphorylated at Ser-3233 by CK2alpha in schizonts. Does not affect merozoite invasion of host erythrocytes (PubMed:12606570). However, merozoites invade either neuraminidase- or trypsin-treated erythrocytes at a significantly lower efficiency than the wild-type (PubMed:12606570). Invasion of erythrocytes treated with both neuraminidase and trypsin is further impaired (PubMed:12606570). Possible candidate for an effective malaria vaccine as determined by epitope response in sera (PubMed:17653272). Antibodies against the erythrocyte binding domain (EBD) prevent merozoite invasion of host erythrocytes (PubMed:21698217, PubMed:27438226). However, inhibition efficiency varies across isolates due to the variation in RH2b expression levels and can also be affected by the expression levels of RH1, another erythrocyte binding receptor (PubMed:21698217). RH2b expression levels greatly vary between isolates; levels are high in isolates 3D7, K1, 7G8, Pf120 and W2mef, low in isolates HB3 and T996, and undetectable in isolates MCAMP, FCB1, T994 and FCR3 (PubMed:12606570, PubMed:12228308). RH2b gene is missing in isolate D10 (PubMed:11160005). A similar variation in expression affects other reticulocyte-binding proteins such as RH2a and RH1 (PubMed:12228308). 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).