title: A conserved subtilisin-like protein TgSUB1 in microneme organelles of Toxoplasma gondii.
abstract: Proteolytic processing plays a significant role in the process of invasion by the obligate intracellular parasite Toxoplasma gondii. We have cloned a gene, TgSUB1, encoding for a subtilisin-type serine protease found in T. gondii tachyzoites. TgSUB1 protein is homologous to other Apicomplexan and bacterial subtilisins and is processed within the secretory pathway of the parasite. Initial cleavage occurs in the endoplasmic reticulum, after which the protein is transported to micronemes, vesicles that secrete early during host cell invasion. Upon stimulation of microneme secretion, TgSUB1 is cleaved into smaller products that are secreted from the parasite. This secondary processing is inhibited by brefeldin A and serine protease inhibitors. TgSUB1 is a candidate processing enzyme for several microneme proteins cleaved within the secretory pathway or during invasion.
authors.affiliation: Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
authors.forename: S A
authors.initials: SA
authors.lastname: Miller
authors.forename: E M
authors.initials: EM
authors.lastname: Binder
authors.forename: M J
authors.initials: MJ
authors.lastname: Blackman
authors.forename: V B
authors.initials: VB
authors.lastname: Carruthers
authors.forename: K
authors.initials: K
authors.lastname: Kim
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001426:Bacterial Proteins; D001483:Base Sequence; D015153:Blotting, Western; D020126:Brefeldin A / Q000494:pharmacology; D020134:Catalytic Domain; D003001:Cloning, Molecular; D017124:Conserved Sequence; D004268:DNA-Binding Proteins; D015180:Electrophoresis, Gel, Two-Dimensional; D004591:Electrophoresis, Polyacrylamide Gel; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D020224:Expressed Sequence Tags; D005656:Fungal Proteins / Q000737:chemistry*; D008854:Microscopy, Electron; D016253:Microscopy, Immunoelectron; D008861:Microsomes / Q000378:metabolism; D008969:Molecular Sequence Data; D011233:Precipitin Tests; D011485:Protein Binding; D015800:Protozoan Proteins; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry; D013381:Subtilisins / Q000096:biosynthesis* / Q000737:chemistry*; D013997:Time Factors; D014122:Toxoplasma / Q000737:chemistry*; D014157:Transcription Factors / Q000737:chemistry*
chemical_list: D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D005656:Fungal Proteins; D015800:Protozoan Proteins; C101206:SUB1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D020126:Brefeldin A; C443133:SUB1 protein, Toxoplasma gondii; D012697:Serine Endopeptidases; D013381:Subtilisins