title: Dematin, a human erythrocyte cytoskeletal protein, is a substrate for a recombinant FIKK kinase from Plasmodium falciparum.
abstract: P. falciparum causes the most deadly form of malaria, resulting from the adherence of infected red blood cells to blood vessels. During the blood stage of infection, the parasite secretes a large number of proteins into the host erythrocyte. The secretion of a 20-member family of protein kinases known as FIKK kinases, after a conserved Phe-Ile-Lys-Lys sequence motif, is unique to P. falciparum. Identification of physiological substrates of these kinases may provide perspective on the importance of FIKK kinase activity to P. falciparum virulence. We demonstrate, for the first time, the heterologous expression and purification of a FIKK kinase (PfFk4.1, PFD1165w). The recombinant kinase is active against general substrates and phosphorylates itself. Having demonstrated kinase activity, we incubated recombinant Fk4.1 with parasite and human erythrocyte lysates. No parasite-derived substrates were identified. However, treatment of erythrocyte ghosts shows that the FIKK kinase Fk4.1 phosphorylates dematin, a cytoskeletal protein found at the red blood cell spectrin-actin junction.
authors: Department of Biochemistry and Molecular Biology, Johns Hopkins University, Bloomberg School of Public Health, Baltimore, MD 21205, United States.
authors: Gabriel S
authors: GS
authors: Brandt
authors: Scott
authors: S
authors: Bailey
mesh_terms: D003001:Cloning, Molecular; D004912:Erythrocytes / Q000469:parasitology*; D015870:Gene Expression; D006801:Humans; D008840:Microfilament Proteins / Q000378:metabolism*; D010766:Phosphorylation; D010770:Phosphotransferases / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000378:metabolism*; D011499:Protein Processing, Post-Translational; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: C044805:DMTN protein, human; D008840:Microfilament Proteins; D011994:Recombinant Proteins; D010770:Phosphotransferases
keywords: Autophosphorylation; Dematin; FIKK kinase; FIKK kinase encoded on chromosome 8; FIKK kinase from P. falciparum; Fk4.1k; Fk8; GLUT1; IMAC; JHMRI; Johns Hopkins Bloomberg School of Public Health Malaria Research Institute; KESTREL; Malaria; PDB; PEXEL; Pathogen kinase; Pf; PfFk; Phe-Ile-Lys-Lys-containing kinase; Plasmodium falciparum; Protein Data Bank; WHO; World Health Organization; glucose transporter 1; iRBC; immobilized metal affinity chromatography; infected red blood cell; kinase domain of Fk4.1; kinase substrate tracking and elucidation; plasmodium export element