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The mammalian HRD1-SEL1L complex provides a scaffold for endoplasmic reticulum (ER)-associated degradation (ERAD), thereby connecting luminal substrates for ubiquitination at the cytoplasmic surface after their retrotranslocation through the endoplasmic reticulum membrane. In this study the stability of the mammalian HRD1-SEL1L complex was assessed by performing siRNA-mediated knockdown of each of its components. Although endogenous SEL1L is a long-lived protein, the half-life of SEL1L was greatly reduced when HRD1 is silenced. Conversely, transiently expressed SEL1L was rapidly degraded but was stabilized when HRD1 was coexpressed. This was in contrast to the yeast Hrd1p-Hrd3p, where Hrd1p is destabilized by the depletion of Hrd3p, the SEL1L homologue. Endogenous HRD1-SEL1L formed a large ERAD complex (Complex I) associating with numerous ERAD components including ERAD lectin OS-9, membrane-spanning Derlin-1/2, VIMP, and Herp, whereas transiently expressed HRD1-SEL1L formed a smaller complex (Complex II) that was associated with OS-9 but not with Derlin-1/2, VIMP, or Herp. Despite its lack of stable association with the latter components, Complex II supported the retrotranslocation and degradation of model ERAD substrates ␣1-antitrypsin null Hong-Kong (NHK) and its variant NHK-QQQ lacking the N-glycosylation sites. NHK-QQQ was rapidly degraded when SEL1L was transiently expressed, whereas the simultaneous transfection of HRD1 diminished that effect. SEL1L unassociated with HRD1 was degraded by the ubiquitin-proteasome pathway, which suggests the involvement of a ubiquitin-ligase other than HRD1 in the rapid degradation of both SEL1L and NHK-QQQ. These results indicate that the regulation of the stability and assembly of the HRD1-SEL1L complex is critical to optimize the degradation kinetics of ERAD substrates.

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The rapid progress of information technology (IT) may provide us with new insights into understanding traffic phenomena, and could help mitigate traffic problems. One of the key applications of IT to traffic and transport analysis is the identification of the location of moving objects using the Global Positioning System (GPS). It is expected that detailed traffic analysis could be carried out using these data. In this article, we first summarize the various applications of probe data in transport analysis. GPS data are merely a sequence of locations, and further data transformation such as map-matching, data-reduction, processing, and reporting is needed to use them effectively. We then discuss the application of bus probe data to evaluating travel time variability and the level of service (LOS) of roads. A methodology for evaluating the road network from the viewpoint of travel time stability and reliability using busThe rapid progress of IT may provide us new insights into understanding traffic phenomena, and could help mitigate traffic problems. One of the key applications of IT to traffic and transport analysis is the identification of the location of moving objects using GPS. It is expected that detailed traffic analysis could be carried out using these data.GPS consists of a series of satellites that orbit the earth, broadcasting signals to receivers on the ground. A receiver can determine its location using data from at least four satellites. GPS was developed by the U.S. Department of Defense for military purposes, and was opened for public use in 1984. There are now 31 GPS satellites available. The performance of the GPS had, This research was supported by the Innovation and Integration of Technologies for a New Society project funded by the Japanese Ministry of Land, Infrastructure, and Management. We wish to thank the Institute of Systems Science Research and our former students, Yusuke Nagahiro and Yusuke Yamawaki, for supporting the analysis of bus probe data.Address correspondence to Nobuhiro Uno, Department of Urban Management, Kyoto University, Kyoto, Japan. E-mail: uno@trans.kuciv.kyotou.ac.jp in the past, been limited by artificial degradation of the signal through the process of selective availability (SA), but the US Government removed that on May 1, 2000. Ochieng and Sauer (2002) reported that the 74% of data are accurate within 10 m without SA, compared to only 24% with SA. Furthermore, no significant difference is apparent between the level of accuracy achievable with differential positioning and post-SA stand-alone navigation.Zito and colleagues (1995) were the first to address the use of GPS data for traffic engineering. They discussed the accuracy of the GPS and its potential for traffic analysis, and suggested that geographical information systems (GIS) could be used efficiently for managing the data obtained by the GPS. They demonstrated that, whenever possible, the direct GPS speed should be used because calculating a speed using the time between two locations gives poor results....

The stability of road networks has become an increasingly important issue in recent times, since the value of time has increased considerably and unexpected delay can results in substantial loss to road users. Road network reliability has now become an important performance measure for evaluating road networks, especially when considering changes in OD traffic demand and link flow capacity over time.This paper outlines the basic concepts, remaining problems and future directions of road network reliability analysis. There are two common definitions of road network reliability, namely, connectivity reliability and travel time reliability. As well, reliability analysis is generally undertaken in both normal and abnormal situations. In order to analyse the reliability of a road network, the reliability of the links within the network must be first determined.

Bdellovibrio bacteriovorus cells have a single polar flagellum whose helical pitch and diameter characteristically change near the midpoint, resulting in a tapered wave. There are six flagellin genes in the genome: fliC1 to fliC6. Accordingly, the flagellar filament is composed of several similar flagellin species. We have used knockout mutants of each gene and analyzed the mutational effects on the filament length and on the composition and localization of each flagellin species in the filament by electron microscopy and one- and two-dimensional polyacrylamide gel electrophoresis. The location and amounts of flagellins in a filament were determined to be as follows: a small amount of FliC3 at the proximal end, followed by a large amount of FliC5, a large amount of FliC1, a small amount of FliC2 in this order, and a large amount of FliC6 at the distal end. FliC4 was present at a low level, but the location was not determined. Filament lengths of newly born progeny cells increased during prolonged incubation in nutrient-deficient buffer. The newly formed part of the elongated filament was composed of mainly FliC6. Reverse transcription PCR analysis of flagellar gene expression over 5 days in buffer showed that fliC gene expression tailed off over 5 days in the wild-type cells, but in the fliC5 mutant, expression of the fliC2, fliC4, and fliC6 genes was elevated on day 5, suggesting that they may be expressed to compensate for the absence of a major component, FliC5.

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