Proteolytic activity of Plasmodium falciparum subtilisin-like protease 3 on parasite profilin, a multifunctional protein.
Subtilisin-like proteases of malaria parasite Plasmodium falciparum (PfSUB1, 2 and 3) are expressed at late asexual blood stages. PfSUB1 and 2 are considered important drug targets due to their essentiality for parasite blood stages and role in merozoite egress and invasion of erythrocytes. We have earlier shown the in vitro serine protease activity of PfSUB3 and its localization at asexual blood stages. In this study, we attempted to identify the biological substrate(s) of PfSUB3 and found parasite profilin (PfPRF) as a substrate of the protease. Eukaryotic profilins are multifunctional proteins with primary role in regulation of actin filament assembly. PfPRF possesses biochemical features of eukaryotic profilins and its rodent ortholog is essential in blood stages. Profilin from related apicomplexan parasite Toxoplasma gondii (TgPRF) is known to be involved in parasite motility, host cell invasion, active egress from host cell, immune evasion and virulence in mice. In this study, mature PfSUB3 proteolysed recombinant PfPRF in a dose-dependent manner in in vitro assays. Recombinant PfPRF was assessed for its proinflammatory activity and found to induce high level of TNF-α and low but significant level of IL-12 from mouse bone marrow-derived dendritic cells. Proteolysis of PfPRF by PfSUB3 is suggestive of the probable role of the protease in the processes of motility, virulence and immune evasion.
Malaria Research Group, International Centre for Genetic Engineering and Biotechnology, P.O. Box 10504, Aruna Asaf Ali Marg, New Delhi 110067, India.
Asrar
A
Alam
Raj K
RK
Bhatnagar
Udbhav
U
Relan
Paushali
P
Mukherjee
Virander S
VS
Chauhan
D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D003713:Dendritic Cells / Q000378:metabolism / Q000469:parasitology; D006801:Humans; D018664:Interleukin-12 / Q000235:genetics / Q000378:metabolism; D016778:Malaria, Falciparum / Q000235:genetics / Q000378:metabolism / Q000469:parasitology*; D051379:Mice; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000235:genetics / Q000378:metabolism; D051304:Profilins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D059748:Proteolysis; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D020860:Subtilisin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism
D051304:Profilins; D015800:Protozoan Proteins; D014409:Tumor Necrosis Factor-alpha; D018664:Interleukin-12; D020860:Subtilisin
FITC; IL-12; Malaria; Plasmodium falciparum; Profilin; SD; Subtilisin-like protease; TLR; TNF-α; fluoresceine isothiocyanate; interleukin 12; synthetic defined; toll-like receptor; tumor necrosis factor-alpha