C1A cysteine-proteases and their inhibitors in plants.
Plant cysteine-proteases (CysProt) represent a well-characterized type of proteolytic enzymes that fulfill tightly regulated physiological functions (senescence and seed germination among others) and defense roles. This article is focused on the group of papain-proteases C1A (family C1, clan CA) and their inhibitors, phytocystatins (PhyCys). In particular, the protease-inhibitor interaction and their mutual participation in specific pathways throughout the plant's life are reviewed. C1A CysProt and PhyCys have been molecularly characterized, and comparative sequence analyses have identified consensus functional motifs. A correlation can be established between the number of identified CysProt and PhyCys in angiosperms. Thus, evolutionary forces may have determined a control role of cystatins on both endogenous and pest-exogenous proteases in these species. Tagging the proteases and inhibitors with fluorescence proteins revealed common patterns of subcellular localization in the endoplasmic reticulum-Golgi network in transiently transformed onion epidermal cells. Further in vivo interactions were demonstrated by bimolecular fluorescent complementation, suggesting their participation in the same physiological processes.
Centro de Biotecnología y Genómica de Plantas (UPM-INIA), Campus Montegancedo, Universidad Politécnica de Madrid, 28223 Pozuelo de Alarcón, Madrid, Spain.
Manuel
M
Martínez
Inés
I
Cambra
Pablo
P
González-Melendi
María E
ME
Santamaría
Isabel
I
Díaz
D015853:Cysteine Proteinase Inhibitors / Q000737:chemistry*; D004721:Endoplasmic Reticulum / Q000201:enzymology; D004789:Enzyme Activation; D019143:Evolution, Molecular; D015971:Gene Expression Regulation, Enzymologic; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant; D018525:Germination; D010206:Papain / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D063245:Plant Development; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D010944:Plants / Q000201:enzymology* / Q000235:genetics; D021381:Protein Transport; D059748:Proteolysis; D012639:Seeds / Q000201:enzymology / Q000502:physiology
D015853:Cysteine Proteinase Inhibitors; D010940:Plant Proteins; D010206:Papain