TY - JOUR
T1 - pfmdr2 confers heavy metal resistance to Plasmodium falciparum
AU - Rosenberg, Elli
AU - Litus, Ilena
AU - Schwarzfuchs, Nurit
AU - Sinay, Rosa
AU - Schlesinger, Pnina
AU - Golenser, Jacob
AU - Baumeister, Stefan
AU - Lingelbach, Klaus
AU - Pollack, Yaakov
PY - 2006/9/15
Y1 - 2006/9/15
N2 - Heavy metals are required by all organisms for normal function, but high levels of heavy metals are toxic. Therefore, homeostasis of these metals is crucial. In the human malaria-causing agent Plasmodium falciparum, the mechanisms of heavy metal transport have yet to be characterized. We have developed a P. falciparum line resistant to heavy metals from a wild-type line sensitive to heavy metals. A molecular and biochemical analysis of the involvement of the P. falciparum multidrug resistance 2 (pfmdr2) gene, an ABC-type transporter, in heavy metal homeostasis was studied. Using a novel uptake assay applied on these two strains, it was demonstrated that, when exposed to heavy metals, the sensitive line accumulates metal, whereas no accumulation was observed in the resistant line. The accumulation occurs within the parasite itself and not in the cytoplasm of the red blood cell. This difference in the accumulation pattern is not a result of amplification of the pfmdr2 gene or of a change in the expression pattern of the gene in the two lines. Sequencing of the gene from both lines revealed a major difference; a stop codon is found in the sensitive line upstream of the normal termination, resulting in a truncated protein that lacks 188 amino acids that contain a portion of the essential cytoplasmatic transporter domain, thereby rendering it inactive. In contrast, the resistant line harbors a full-length, active protein. These findings strongly suggest that the PFMDR2 protein acts as an efflux pump of heavy metals.
AB - Heavy metals are required by all organisms for normal function, but high levels of heavy metals are toxic. Therefore, homeostasis of these metals is crucial. In the human malaria-causing agent Plasmodium falciparum, the mechanisms of heavy metal transport have yet to be characterized. We have developed a P. falciparum line resistant to heavy metals from a wild-type line sensitive to heavy metals. A molecular and biochemical analysis of the involvement of the P. falciparum multidrug resistance 2 (pfmdr2) gene, an ABC-type transporter, in heavy metal homeostasis was studied. Using a novel uptake assay applied on these two strains, it was demonstrated that, when exposed to heavy metals, the sensitive line accumulates metal, whereas no accumulation was observed in the resistant line. The accumulation occurs within the parasite itself and not in the cytoplasm of the red blood cell. This difference in the accumulation pattern is not a result of amplification of the pfmdr2 gene or of a change in the expression pattern of the gene in the two lines. Sequencing of the gene from both lines revealed a major difference; a stop codon is found in the sensitive line upstream of the normal termination, resulting in a truncated protein that lacks 188 amino acids that contain a portion of the essential cytoplasmatic transporter domain, thereby rendering it inactive. In contrast, the resistant line harbors a full-length, active protein. These findings strongly suggest that the PFMDR2 protein acts as an efflux pump of heavy metals.
UR - http://www.scopus.com/inward/record.url?scp=33748749415&partnerID=8YFLogxK
U2 - 10.1074/jbc.M601686200
DO - 10.1074/jbc.M601686200
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C2 - 16849328
AN - SCOPUS:33748749415
SN - 0021-9258
VL - 281
SP - 27039
EP - 27045
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 37
ER -