Disease relevance of ORT1

• The yeast ARG-11 protein has been over-produced as inclusion bodies in Escherichia coli [1].

High impact information on ORT1

• We have used immuno-Western blotting and hemagglutinin epitope-tagged derivatives of Arg11p, Arg8p (a mitochondrial matrix marker), and Arg3p (a cytosolic marker) to demonstrate that Arg11p is confined to the mitochondria and behaves like an integral membrane protein [2].
• A deletion created in ARG11 causes the same arginine-leaky behavior as the original arg11-1 mutation, which yields a premature stop codon at residue 266 [2].
• As a working hypothesis, we propose that Arg11p participates in the export of matrix-made ornithine into the cytosol [2].
• We show that the ARG11 open reading frame encodes a putative 292-residue protein with a predicted molecular mass of 31.5 kDa [2].
• We describe the identification and functional characterization of two Arabidopsis mitochondrial basic amino acid carriers (BAC), AtmBAC1 and AtmBAC2, which are related to the yeast ornithine (Orn) carrier Ort1p, also known as Arg11p [3].

Biological context of ORT1

• The ARG-11 gene in Saccharomyces cerevisiae encodes a protein with the characteristic features of a family of 35 related membrane proteins that are encoded in the fungal genome [1].
• Evidence is presented here that the mitochondrial inner membrane contains an L-arginine and L-ornithine transporting system distinct from Arg11p, in keeping with the arginine leaky phenotype of arg11 knock-out mutants [4].

Associations of ORT1 with chemical compounds

• This emerged from the following observations: (a) the derepressive effect disappears if any extra piece of DNA is inserted upstream from the ARG2 promoter; and (b) similar derepression on low glucose is observed with another yeast promoter (ARG11), provided that the flanking 5' region is short [5].
• In this work we have characterised the transport of L-arginine and L-ornithine into mitochondria isolated from a wild-type Saccharomyces cerevisiae strain and an isogenic arg11 knock-out mutant [4].
• AtmBAC1 recognized l-histidine whereas both yeast Ort1p and the mammalian ortholog ORNT1p do not [3].

Analytical, diagnostic and therapeutic context of ORT1

• The present study utilizes site-directed mutagenesis to evaluate the catalytic importance of 7 residues of human prostatic phosphatase, namely His12, His257, Asp258, Arg11, Arg15, Arg54, and Arg79, which are highly conserved in the sequences of high molecular weight acid phosphatases [6].

References