caa a22 4500 467950431 CHVBK 20180405193741.0 cr unu---uuuuu 170328e20041201xx s 000 0 eng 10.1007/BF02637252 doi (NATIONALLICENCE)springer-10.1007/BF02637252 (NATIONALLICENCE)springer-10.1007/s00344-004-0409-4 A protease activity displaying some thrombin-like characteristics in conditioned medium of zinnia mesophyll cells undergoing tracheary element differentiation [Elektronische Daten] [Xiao-Hong Yu, Brian Jones, Alan Jones, Yair Heimer] The normal development of tracheary elements (TE) requires a selective degradation of the cytoplasm without loss of the extracellular wall that remains behind as the water-conducting units of xylem. Using zinnia-(Zinnia elegans L. cv. Green Envy) cultured mesophyll cells that synchronously transdifferentiate into TEs, extracellular and intracellular proteases, respectively, have been shown to both trigger death and to execute autolysis as the final component of a programmed cell death (PCD). We report here the appearance in the medium of an unusual proteolytic activity correlated with the PCD process just prior to the autolysis. The activity has a pH optimum of 5.5-6.0 and displays some thrombin characteristics. This protease activity has 1) a 10-fold higher affinity towards a thrombin-specific chromogenic substrate than toward a trypsin-specific chromogenic substrate; 2) a 1000-fold lower sensitivity to soybean trypsin inhibitor (STI) compared to trypsin; and 3) limited ability to cleave the protease-activated receptor-1, the native thrombin substrate. However, the addition of partially purified fraction containing the thrombin-like protease activity to the medium of PCD-competent cells does not prematurely trigger PCD, and the thrombin-specific peptide inhibitor phenylalanine-proline-aspartic acid-chloromethylketone fails to inhibit PCD or tracheary element (TE) formation. This suggests that this protease activity may play a role within the cells in execution of the autolysis or in the collapse of the tonoplast rather than as an extracellular proteolytic activity participating in the chain of events leading to cell death. Springer Science-Business Media, Inc, 2005 Zinnia nationallicence Programmed cell death nationallicence Thrombin nationallicence Tracheary elements nationallicence Zinnia nationallicence Yu Xiao-Hong Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut Jones Brian Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut Jones Alan Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut Heimer Yair Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut Journal of Plant Growth Regulation Springer-Verlag 23/4(2004-12-01), 292-300 0721-7595 23:4<292 2004 23 344 https://doi.org/10.1007/BF02637252 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02637252 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yu Xiao-Hong Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut NATIONALLICENCE 700 1- Jones Brian Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut NATIONALLICENCE 700 1- Jones Alan Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut NATIONALLICENCE 700 1- Heimer Yair Department of Biology, University of North Carolina at Chapel Hill, 25799, Chapel Hill, NC, USA aut NATIONALLICENCE 773 0- Journal of Plant Growth Regulation Springer-Verlag 23/4(2004-12-01), 292-300 0721-7595 23:4<292 2004 23 344 NATIONALLICENCE 856 40 https://doi.org/10.1007/s00344-004-0409-4 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Yu Xiao-Hong Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 25799, USA aut NATIONALLICENCE 700 1- Jones Brian Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 25799, USA aut NATIONALLICENCE 700 1- Jones Alan Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 25799, USA aut NATIONALLICENCE 700 1- Heimer Yair Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 25799, USA aut NATIONALLICENCE 773 0- Journal of Plant Growth Regulation Springer-Verlag; www.springer-ny.com 23/4(2004-12-01), 292-300 0721-7595 23:4<292 2004 23 344 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer NATIONALLICENCE NATIONALLICENCE NL-springer