title: A high specificity and affinity interaction with serum albumin stimulates an anion conductance in malaria-infected erythrocytes.
abstract: The intraerythrocytic development of P. falciparum induces New Permeability Pathways (NPP) in the membrane of the parasitized erythrocyte which provide the parasite with nutrients, adjust the erythrocyte electrolyte composition to the needs of the parasite, and dispose of metabolic waste products and osmolytes. Patch-clamp recordings identified inwardly and outwardly rectifying (OR) anion conductances in the host erythrocyte membrane as electrophysiological correlate of the NPP. The OR conductance is regulated by serum. Here we show that serum albumin (SA) stimulated OR-generated Cl(-) and lactate outward currents with an EC(50) of approximately 100 nM while other proteins such as ovalbumin or casein did not. The stimulatory efficacy did not differ between fatty acid free bovine SA and recombinant human SA and disruption of the SA tertiary structure abolished the effect suggesting that intact SA protein and not other bound factors interact with the erythrocyte membrane. Taken together, the data indicate a high affinity and specificity interaction of native SA with the parasitized erythrocytes which might underlie the observed dependence of P. falciparum growth in vitro on SA.
authors.affiliation: Department of Physiology, University of Tübingen, Tübingen, Tübingen, Germany.
authors.forename: Christophe
authors.initials: C
authors.lastname: Duranton
authors.forename: Valerie
authors.initials: V
authors.lastname: Tanneur
authors.forename: Camelia
authors.initials: C
authors.lastname: Lang
authors.forename: Verena B
authors.initials: VB
authors.lastname: Brand
authors.forename: Saisudha
authors.initials: S
authors.lastname: Koka
authors.forename: Ravi S
authors.initials: RS
authors.lastname: Kasinathan
authors.forename: Martina
authors.initials: M
authors.lastname: Dorsch
authors.forename: Hans J
authors.initials: HJ
authors.lastname: Hedrich
authors.forename: Stefan
authors.initials: S
authors.lastname: Baumeister
authors.forename: Klaus
authors.initials: K
authors.lastname: Lingelbach
authors.forename: Florian
authors.initials: F
authors.lastname: Lang
authors.forename: Stephan M
authors.initials: SM
authors.lastname: Huber
mesh_terms: D000818:Animals; D002364:Caseins / Q000494:pharmacology; D018118:Chloride Channels / Q000378:metabolism; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism* / Q000469:parasitology*; D006801:Humans; D015640:Ion Channel Gating / Q000187:drug effects; D019344:Lactic Acid / Q000378:metabolism; D008288:Malaria / Q000378:metabolism*; D010047:Ovalbumin / Q000494:pharmacology; D010963:Plasmodium falciparum / Q000187:drug effects / Q000378:metabolism*; D011994:Recombinant Proteins / Q000378:metabolism; D012709:Serum Albumin / Q000378:metabolism*; D012710:Serum Albumin, Bovine / Q000494:pharmacology
chemical_list: D002364:Caseins; D018118:Chloride Channels; D011994:Recombinant Proteins; D012709:Serum Albumin; D012710:Serum Albumin, Bovine; D019344:Lactic Acid; D010047:Ovalbumin