BP-80, later renamed VSR PS-1 , is a putative receptor involved in sorting proteins such as proaleurain to the lytic vacuole, with its N-terminal domain recognizing the vacuolar sorting determinant. Although all VSR PS-1 characteristics and in vitro binding properties described so far favored its receptor function, this function remained to be demonstrated. Here, we used green fluorescent protein (GFP) as a reporter in a yeast mutant strain defective for its own vacuolar receptor, Vps10p. By expressing VSR PS-1 together with GFP fused to the vacuolar sorting determinant of petunia proaleurain, we were able to efficiently redirect the reporter to the yeast vacuole. VSR PS-1 is ineffective on GFP either alone or when fused with another type of plant vacuolar sorting determinant from a chitinase. The plant VSR PS-1 therefore interacts specifically with the proaleurain vacuolar sorting determinant in vivo, and this interaction leads to the transport of the reporter protein through the yeast secretory pathway to the vacuole. This finding demonstrates VSR PS-1 receptor function but also emphasizes the differences in the spectrum of ligands between Vps10p and its plant equivalent. INTRODUCTIONThe plant secretory system is far less easy to study than its yeast counterpart, mainly due to the lack of an equivalent mutant collection. Plant and yeast cells, in opposition to mammalian cells, do not use the mannose 6-phosphatebased lysosomal sorting tag (Kornfeld, 1992); instead, the sorting information is carried by a peptidic sequence. In yeast, the two vacuolar proteins carboxypeptidase Y (CPY; Johnson et al., 1987) and proteinase A (Klionsky and Emr, 1989) both are produced with an N-terminal propeptide responsible for the vacuolar location of the mature protein. Almost 50 mutants defective for vacuolar protein sorting ( vps ) have allowed the identification of proteins involved in the yeast vacuolar sorting pathway. One of these proteins, Vps10p, plays a central role because it is the vacuolar receptor for CPY (Marcusson et al., 1994). Vps10p also is able to send foreign or malfolded proteins to the vacuole for degradation in a process that is believed to be independent of any sorting signal (Hong et al., 1996).In plants, two main types of vacuolar sorting determinants (VSDs) have been well studied and are believed to correspond to two separate vacuolar sorting pathways. The first type could be defined as a sequence-specific VSD (ssVSD) and has been well studied for barley aleurain (Holwerda et al., 1992) and sweet potato sporamin A (Matsuoka and Nakamura, 1991). For these two examples, the VSD is located within an N-terminal propeptide and contains a conserved tetrapeptide NPIR, the Ile being essential (Matsuoka and Nakamura, 1999). The position of this category of VSD seems to be less important than its sequence specificity, as shown with sporamin A (Koide et al., 1997). The second type of VSD is found in C-terminal propeptides (Ct-VSD); it is rather short with no obvious sequence conservation but needs to be accessibl...

A new test rig has been designed, built and commissioned, and is now jointly pursued to facilitate experimental investigations into advanced combustion processes (i.e., dual fuel, multi-mode) under turbulent conditions at high, engine-like temperature and pressure levels. Based on a standard diesel engine block, it offers much improved optical access to the in-cylinder processes due to its separated and rotated arrangement of the compression volume and combustion chamber, respectively. A fully variable pneumatic valve train and the appropriate preconditioning of the intake air allows it to represent a wide range of engine-like in-cylinder conditions regarding pressures, temperatures and turbulence levels. The modular design of the test rig facilitates easy optimizations of the combustion chamber/cylinder head design regarding different experimental requirements. The name of the new test rig, Flex-OeCoS, denotes its Flexibility regarding Optical engine Combustion diagnostics and/or the development of corresponding Sensing devices and applications. Measurements regarding in-cylinder gas pressures, temperatures and the flow field under typical operating conditions are presented to complete the description and assessment of the new test rig.

BP-80, later renamed VSR PS-1 , is a putative receptor involved in sorting proteins such as proaleurain to the lytic vacuole, with its N-terminal domain recognizing the vacuolar sorting determinant. Although all VSR PS-1 characteristics and in vitro binding properties described so far favored its receptor function, this function remained to be demonstrated. Here, we used green fluorescent protein (GFP) as a reporter in a yeast mutant strain defective for its own vacuolar receptor, Vps10p. By expressing VSR PS-1 together with GFP fused to the vacuolar sorting determinant of petunia proaleurain, we were able to efficiently redirect the reporter to the yeast vacuole. VSR PS-1 is ineffective on GFP either alone or when fused with another type of plant vacuolar sorting determinant from a chitinase. The plant VSR PS-1 therefore interacts specifically with the proaleurain vacuolar sorting determinant in vivo, and this interaction leads to the transport of the reporter protein through the yeast secretory pathway to the vacuole. This finding demonstrates VSR PS-1 receptor function but also emphasizes the differences in the spectrum of ligands between Vps10p and its plant equivalent. INTRODUCTIONThe plant secretory system is far less easy to study than its yeast counterpart, mainly due to the lack of an equivalent mutant collection. Plant and yeast cells, in opposition to mammalian cells, do not use the mannose 6-phosphatebased lysosomal sorting tag (Kornfeld, 1992); instead, the sorting information is carried by a peptidic sequence. In yeast, the two vacuolar proteins carboxypeptidase Y (CPY; Johnson et al., 1987) and proteinase A (Klionsky and Emr, 1989) both are produced with an N-terminal propeptide responsible for the vacuolar location of the mature protein. Almost 50 mutants defective for vacuolar protein sorting ( vps ) have allowed the identification of proteins involved in the yeast vacuolar sorting pathway. One of these proteins, Vps10p, plays a central role because it is the vacuolar receptor for CPY (Marcusson et al., 1994). Vps10p also is able to send foreign or malfolded proteins to the vacuole for degradation in a process that is believed to be independent of any sorting signal (Hong et al., 1996).In plants, two main types of vacuolar sorting determinants (VSDs) have been well studied and are believed to correspond to two separate vacuolar sorting pathways. The first type could be defined as a sequence-specific VSD (ssVSD) and has been well studied for barley aleurain (Holwerda et al., 1992) and sweet potato sporamin A (Matsuoka and Nakamura, 1991). For these two examples, the VSD is located within an N-terminal propeptide and contains a conserved tetrapeptide NPIR, the Ile being essential (Matsuoka and Nakamura, 1999). The position of this category of VSD seems to be less important than its sequence specificity, as shown with sporamin A (Koide et al., 1997). The second type of VSD is found in C-terminal propeptides (Ct-VSD); it is rather short with no obvious sequence conservation but needs to be accessibl...