Malaria parasites: enzymes involved in red blood cell invasion.
Three enzymes have been described in malaria merozoites: a serine-protease and two phospholipases. The parasite serine-protease is necessary for parasite entry into the red blood cell. This enzyme is synthesized by intraerythrocytic schizonts as a glycolipid-anchored membrane precursor, harbouring a preformed serine-protease active site but no detectable proteolytic activity. Detection of the enzymatic activity correlates with the solubilisation of the enzyme by a parasite glycolipid-specific phospholipase C in merozoites. A third enzyme has been detected with glycolipid-degrading activity, presumably a lipase A. These activities participate in a biochemical cascade originating with the attachment of the merozoite to the red blood cell, including the translocation of the phospholipase C to the membrane-bound protease, the solubilisation/activation of the protease and its secretion at the erythrocyte/parasite junction and ending with the entry of the parasite into the host cell. Both the phospholipase C and the lipase A might generate secondary messages in the merozoite. Our current knowledge concerning these enzymes is presented.
Braun-Breton
C
C
Unit of Experimental Parasitology, Institut Pasteur, Paris, France.
Blisnick
T
T
Morales-Betoulle
M E
ME
Barale
J C
JC
Langsley
G
G
D000818:Animals; D004912:Erythrocytes / Q000469:parasitology*; D008049:Lipase / Q000097:blood*; D008288:Malaria / Q000097:blood* / Q000201:enzymology; D010961:Plasmodium / Q000201:enzymology / Q000502:physiology*; D012697:Serine Endopeptidases / Q000097:blood*; D010738:Type C Phospholipases / Q000097:blood*
D008049:Lipase; D010738:Type C Phospholipases; D012697:Serine Endopeptidases