Ricinosomes: an organelle for developmentally regulated programmed cell death in senescing plant tissues

Die Naturwissenschaften
Christine Gietl, M Schmid

Abstract

This review describes aspects of programmed cell death (PCD). Present research maps the enzymes involved and explores the signal transduction pathways involved in their synthesis. A special organelle (the ricinosome) has been discovered in the senescing endosperm of germinating castor beans (Ricinus communis) that develops at the beginning of PCD and delivers large amounts of a papain-type cysteine endopeptidase (CysEP) in the final stages of cellular disintegration. Castor beans store oil and proteins in a living endosperm surrounding the cotyledons. These stores are mobilized during germination and transferred into the cotyledons. PCD is initiated after this transfer is complete. The CysEP is synthesized in the lumen of the endoplasmic reticulum (ER) where it is retained by its C-terminal KDEL peptide as a rather inactive pro-enzyme. Large number of ricinosomes bud from the ER at the same time as the nuclear DNA is characteristically fragmented during PCD. The mitochondria, glyoxysomes and ribosomes are degraded in autophagic vacuoles, while the endopeptidase is activated by removal of the propeptide and the KDEL tail and enters the cytosol. The endosperm dries and detaches from the cotyledons. A homologous KDEL-tailed cystei...Continue Reading

Citations

Mar 8, 2005·Trends in Plant Science·Wouter G van Doorn, Ernst J Woltering
Dec 23, 2008·Plant Physiology·Adriano SenatoreJohn S Greenwood
Feb 3, 2005·Proceedings of the National Academy of Sciences of the United States of America·John S GreenwoodChristine Gietl
Dec 31, 2003·Phytochemistry·Eric P BeersAllan W Dickerman
Jul 29, 2003·Proceedings of the National Academy of Sciences of the United States of America·Uwe SchumannChristine Gietl
May 14, 2010·Journal of Plant Physiology·Belén Esteban-GarcíaFederico García-Maroto
Nov 8, 2008·Science in China. Series C, Life Sciences·ShuMin ZhouMao Wang
Sep 3, 2004·The Plant Journal : for Cell and Molecular Biology·Nicholas A JolliffeLorenzo Frigerio
Feb 13, 2003·The Plant Journal : for Cell and Molecular Biology·Ryo MatsushimaIkuko Hara-Nishimura
Jun 16, 2006·The Journal of Biological Chemistry·Nicholas A JolliffeLynne M Roberts
Dec 22, 2019·International Journal of Molecular Sciences·Inna ChabanElena Smirnova
Oct 27, 2007·Journal of Agricultural and Food Chemistry·Yeh-Jin Ahn, Grace Q Chen

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