PMC:101403 / 9318-10906 JSONTXT

{"project":"2_test","denotations":[{"id":"11943069-1417723-8112326","span":{"begin":235,"end":237},"obj":"1417723"},{"id":"11943069-10446385-8112327","span":{"begin":238,"end":240},"obj":"10446385"},{"id":"11943069-11361135-8112328","span":{"begin":1211,"end":1213},"obj":"11361135"}],"text":"Y87G2A.14 has the C-terminal tripeptide sequence SKI. This conforms to the pattern typical of PTS1 peroxisomal targeting signals found in many peroxisomal matrix proteins, suggesting that Y87G2A.14 may be targeted to these organelles [18,19]. However, possession of a potential PTS1 sequence is not always sufficient on its own to result in peroxisomal targeting and other elements of the protein sequence may also be involved. Since targeting of animal peroxisomal proteins expressed in yeast has often been observed, yeast cells were transformed with expression plasmids encoding C-terminal or N-terminal fusions of Y87G2A.14 to yeast-enhanced green fluorescent protein (yEGFP) in order to determine the subcellular location of Y87G2A.14. The cells were then examined by confocal microscopy. Cells transformed with pY87G2A.14-yEGFP, in which the C-terminus of Y87G2A.14 is fused to the N-terminus of yEGFP, showed a diffuse, cytoplasmic fluorescence with no clear subcellular localization (Fig 4a). In contrast, cells transformed with pyEGFP-Y87G2A.14, in which the C-terminal tripeptide SKI is free to act as a targeting signal showed the clear punctate fluorescence that is indicative of yeast peroxisomes [16] (Fig 4b). The identity of SKI as the targeting signal was confirmed by transformation of cells with pyEGFP-Y87G2A.14Δ SKI, in which the C-terminal tripeptide was deleted during construction. This again showed a diffuse, cytoplasmic, fluorescence (Fig 4c). Together, these results strongly suggest that Y87G2A.14 is targeted to peroxisomes by its C-terminal tripeptide, SKI."}