Table 1.

The invasion-related proteins of the P. falciparum merozoite

NamePlasmoDB accession numberGenetic knockoutLocalization in merozoite before/during invasionPotential functionFeature/structure
GPI-anchored MSPs
MSP-1PF3D7_0930300NSurface/complex shed during invasion with MSP1/19 EGF C-terminal domain retained in PV of ring stagePutative Band 3 ligand; C-terminal double EGF domain redundant for divergent molecules: processed SUB1 and -2Two C-terminal EGF domains: compact side by side arrangement
MSP-2PF3D7_0206800NSurfaceHighly polymorphic; likely structural role as surface coatUnordered repetitive structure
MSP-5PF3D7_0207000NSurfaceNot knownC-terminal EGF domain
MSP-4PF3D7_0206900.1YSurfaceNot knownC-terminal EGF domain
MSP-10PF3D7_0620400NSurfaceNot knownC-terminal EGF domain
Pf12PF3D7_0612700YSurface/shedPotential adhesive protein6-Cys domains
Pf38PF3D7_0508000YSurface/shedPotential adhesive protein6-Cys domains
Pf92PF3D7_1364100YSurface/shedNot knownCys-rich protein
Peripheral surface proteins
Pf113PF3D7_1420700NSurface/shedNot knownNo data
MSP-9 (ABRA)PF3D7_1228600YSurface/shedPutative proteaseNo data
S-antigenPF3D7_1035200NSecreted into PV of schizont and released on egressNot known; potential immunomodulatory roleHighly repetitive and diverse protein
GLURPPF3D7_1035300YSecreted into PV of schizont and released on egressNot knownRepetitive Glutamate-rich
MSP-3PF3D7_1035400YSurface/shedNot known; binds to MSP-1Repetitive and Glutamate-rich
MSP-6PF3D7_1035500YSurface/shedNot known; binds to MSP-1Leucine zipper-like C-terminal domain
H101 (MSP-11)PF3D7_1035600YSurface/shedNot knownMSP-3 family, leucine zipper-like C-terminal domain
H103PF3D7_1035900YSurface/shedNot knownMSP-3 family, leucine zipper-like C-terminal domain
MSP-7PF3D7_1335100YSurface/shedAssociates with MSP-1, gene knockout in P. berghei shows important in invasion of mature erythrocytesNo data
MSP-7-like (MSRP2)PF3D7_1334800YSurface/shedNot known; may associate with MSP-1MSP-7 family
MSPDBL-1PF3D7_1036300YSurface/shedBinds to unknown receptor on red cellMember of EBL family, DBL and leucine zipper-like domains
MSPDBL-2PF3D7_1035700YSurface/shedBinds to unknown receptor on red cellMember of EBL family, DBL and leucine zipper-like domains
SERA3PF3D7_0207800YSecreted into PV of schizont and released on egressCysteine protease domain with active site serineCysteine protease domain
SERA4PF3D7_0207700NMost secreted into PV of schizont and released on egressCysteine protease domain with active site serineCysteine protease domain
SERA5PF3D7_0207600NSecreted into PV of schizont and released on egressCysteine protease domain with active site serineCysteine protease domain
SERA6PF3D7_0207500NMost secreted into PV of schizont and released on egressCysteine protease domain with active site cysteineCysteine protease domain
Pf41PF3D7_0404900YSurface/shedPotential adhesive protein; binds Pf12 on merozoite6-Cys domains
Plasma membrane proteins
ROM1PF3D7_1114100YMononeme (proposed new apical organelle) or microneme/surfaceRhomboid protease; cleaves AMA1, MAEBL, EBLs, PfRh proteins; likely role after invasion in PV formationMultipass transmembrane protein
ROM4PF3D7_0506900NDSurface/shedRhomboid protease; cleaves AMA1, MTRAP, EBL, and PfRh proteins in transmembrane to allow shedding during invasionMultipass transmembrane protein
Microneme proteins
AMA 1PF3D7_1133400NMicronemes/surface and binds to RON2 that has been inserted into red cell membrane and tracks with tight junctionReleased on merozoite surface; binds RON complex; potential ligand for McLeod antigen, phosphorylation of cytoplasmic tail essential, may be involved in signalingPAN (plasminogen, apple, nematode) motifs
EBA-175PF3D7_0731500YaMicronemes/surface and binds to glycophorin ABinds to glycophorin A, likely signaling role for invasionEBL family with DBL domains; “handshake” association between region II dimers creates groove for glycophorin A binding
EBA-181/JESEBLPF3D7_0102500YMicronemes/surface and binds to unknown receptorBinds to unknown receptor on red cellEBL family member with DBL domains
EBA-140/BAEBLPF3D7_1301600YMicronemes/surface and binds to glycophorin CBinds to glycophorin C on red cellEBL family member with DBL domains
EBL-1PF3D7_1371600YNo dataBinds to glycophorin B, nonfunctional because of mutations causing truncated proteinEBL family member with DBL domains
PTRAMPPF3D7_1218000NDNot known; cleaved by SUB2 on merozoite surfaceLong extended structure
PfRiprPF3D7_0323400NMicronemes/surface and binds to PfRh5Binds to PfRh510 EGF domains, 87 cysteines
MTRAPPF3D7_1028700NMicronemes/PVPotential motor-associated proteinThrombospondin-like domains
PTRAMPPF3D7_1218000NMicronemes/surfacePotential motor-associated proteinThrombospondin-like domains
SPATRPF3D7_0405900NDMicronemes/surfaceNot known for blood stagesThrombospondin-like domains
GAMAPF3D7_0828800NDMicronemes/surfaceBinds to red cells; has GPI anchorNo data
SUB2PF3D7_1136900NMicronemes/PVProtease that processes MSP-1, MSP-6, MSP-7, AMA1, PTRAMP and other proteins to prime merozoite for invasionSubtilisin-like serine protease
Exoneme proteins
SUB1PF3D7_0507500NExonemes/PVProtease that processes MSP-1, MSP-6, MSP-7, AMA1, RAP1, MSRP2 and SERAs to prime merozoite for invasionSubtilisin-like serine protease
Rhoptry neck proteins
PfRh1PF3D7_0402300YaRhoptry neck/surfaceBinds to red cells via receptor YPfRh family
PfRh2aPF3D7_1335400YRhoptry neck/surfaceBinds to red cells via receptor ZPfRh family
PfRh2bPF3D7_1335300YRhoptry neck/surfaceBinds to red cells via receptor ZPfRh family
PfRh4PF3D7_0424200YRhoptry neck/surfaceBinds to red cells via complement receptor 1PfRh family
PfRh5PF3D7_0424100NRhoptry neck/surface forms complex with RiprBinds to red cells via BasiginClassed as PfRh family but lacks homology and no transmembrane so likely functionally distinct
RON2PF3D7_1452000NDRhoptry neck/into red cell membraneInserted in red cell membrane at invasion, forms complex at tight junction with RON proteins and AMA-1Multipass transmembrane protein
RON3PF3D7_1252100NDRhoptry neck/into red cellLikely also forms complex at tight junction with other RON proteins and AMA-1No data
RON4PF3D7_1116000NDRhoptry neck/into red cellInjected into red cell, binds to RON2 and forms a complex at tight junction with RON proteins and AMA-1Binds to AMA1 via hydrophobic groove
RON5PF3D7_0817700NDRhoptry neck/into red cellForms complex at tight junction with RON proteins and AMA-1No data
ASPPF3D7_0405900NDRhoptry neck/surfaceNot known; has putative GPI anchorSushi domains
  • N, knockout attempt unsuccessful; Y, knockout generated; ND, knockout not attempted; PV, parasitophorous vacuole; MSP, merozoite surface protein

  • a EBL and PfRh families show overlap in function and, while individually nonessential, overall are essential.