51 research outputs found

    A vacuolar sorting domain may also influence the way in which proteins leave the endoplasmic reticulum

    No full text
    Protein sorting to plant vacuoles is known to be dependent on a considerable variety of protein motifs recognized by a family of sorting receptors. This can involve either traffic from the endoplasmic reticulum (ER) through the Golgi apparatus or direct ER-to-vacuole transport. Barley aspartic protease (Phytepsin) was shown previously to reach the vacuole via trafficking through the Golgi apparatus. Here we show that Phytepsin normally exits the ER in a COPII-mediated manner, because the Phytepsin precursor accumulates in the ER upon specific inhibition of the formation of COPII vesicles in vivo. Phytepsin differs from its yeast and mammalian counterparts by the presence of a saposin-like plant-specific insert (PSI). Deletion of this domain comprising 104 amino acids causes efficient secretion of the truncated molecule (Phytepsin Delta PSI) without affecting the enzymatic activity of the enzyme. Interestingly, deletion of the PSI also changes the way in which Phytepsin exits the ER. Inhibition of COPII vesicle formation causes accumulation of the Phytepsin precursor in the ER but has no effect on the secretion of Phytepsin Delta PSI. This suggests either that vacuolar sorting commences at the ER export step and involves recruitment into COPII vesicles or that the PSI domain carries two signals, one for COPII-dependent export from the ER and one for vacuolar delivery from the Golgi. The relevance of these observations with respect to the bulk flow model of secretory protein synthesis is discussed

    The c-terminal extension of a hybrid immunoglobulin A/G heavy chain is responsible for its Golgi-mediated sorting to the vacuole

    No full text
    We have assessed the ability of the plant secretory pathway to handle the expression of complex heterologous proteins by investigating the fate of a hybrid immunoglobulin A/G in tobacco cells. Although plant cells can express large amounts of the antibody, a relevant proportion is normally lost to vacuolar sorting and degradation. Here we show that the synthesis of high amounts of IgA/G does not impose stress on the plant secretory pathway. Plant cells can assemble antibody chains with high efficiency and vacuolar transport occurs only after the assembled immunoglobulins have traveled through the Golgi complex. We prove that vacuolar delivery of IgA/G depends on the presence of a cryptic sorting signal in the tailpiece of the IgA/G heavy chain. We also show that unassembled light chains are efficiently secreted as monomers by the plant secretory pathway

    ECSPECT prospective multicentre registry for single-port laparoscopic colorectal procedures

    No full text
    Background: The international multicentre registry ECSPECT (European Consensus of Single Port Expertise in Colorectal Treatment) was established to evaluate the general feasibility and safety of single-port colorectal surgery with regard to preoperative risk assessment. Methods: Consecutive patients undergoing single-port colorectal surgery were enrolled from 11 European centres between March 2010 and March 2014. Data were analysed to assess patient-, technique- and procedure-dependent parameters. A validated sex-adjusted risk chart was developed for prediction of single-port colorectal surgery-related conversion and complications. Results: Some 1769 patients were enrolled, 937 with benign and 832 with malignant conditions. Procedures were completed without additional trocars in 1628 patients (92·0 per cent). Conversion to open surgery was required in 75 patients (4·2 per cent) and was related to male sex and ASA fitness grade exceeding I. Conversions were more frequent in pelvic procedures involving the rectum compared with abdominal procedures (8·1 versus 3·2 per cent; odds ratio 2·69, P < 0·001). Postoperative complications were observed in a total of 224 patients (12·7 per cent). Independent predictors of complications included male sex (P < 0·001), higher ASA grade (P = 0·006) and rectal procedures (P = 0·002). The overall 30-day mortality rate was 0·5 per cent (8 of 1769 patients); three deaths (0·2 per cent; 1 blood loss, 2 leaks) were attributable to surgical causes. Conclusion: The feasibility and safety, conversion and complication profile demonstrated here provides guidance for patient selection
    corecore