ELSEVIER Plant Science 99 (1994) I I 1-124 plan ience Review article Phosphoenolpyruvate carboxylase: structure, evolution regulation and Loic Lepiniec *a, Jean Vidal a, Raymond Chollet b, Pierre Gadal a, Claude Cr6tinT a aLaboratoire de Physiologie Vdgdtale Moldculaire, URA CNRS D 1128, Universitd de Paris-Sud, Bdtiment 430, 91405 Orsay Cedex, France bDepartment of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE 68583-0718, USA Received 29 December 1993; revision received 29 March 1994; accepted 18 April 1994 Abstract Plant phosphoenolpyruvate carboxylase (EC 4.1.1.31; PEPC) is encoded by a small multigene family in which the expression of each member is controlled individually by exogenous (light, environmental) and/or endogenous (hor- monal and developmental) stimuli. The involvement of putative trans-acting factors and consensus cis-elements of promoters in the specific transcriptional regulation of the PEPC genes is discussed. At the post-translational level, the regulatory strategy of the plant enzyme is mainly to offset the negative effect of the feedback inhibitor, L-malate, the end-product of the oxaloacetate reduction. All plant PEPC-forms are under positive and negative allosteric control by metabolite effectors and possess a consensus phosphorylation site containing a target serine residue near their N- terminus (e.g. Ser8 in C4 PEPC from sorghum). In C 4 and Crassulacean acid metabolism (CAM) plants, a complex signal-transduction chain activates ~a Ca2+-independent protein-serine kinase responsible for regulatory phosphoryla- tion of PEPC. A more thorough understanding of the functional and regulatory properties of the bacterial and C 4 enzymes has emerged by exploiting recombinant proteins and site-directed mutagenesis. In these newly opened areas, PEPC offers one of the best characterized paradigms of plant signaling. Finally, some emerging ideas on the evolution and phylogenetic relationships of the various PEPC isoforms are presented. Keywords: Phosphoenolpyruvate carboxylase; Gene family; Gene expression; Evolution; Mutagenesis; Phosphory- lation * Corresponding author, Laboratorium Genetika, Ledegan- ckstraat 35, Rijksuniversiteit Gent, B-9000 Gent, Belgium. Tel.: 32 (0) 9264 5192; Fax.: 32 (0) 9264 5349. tWe would like to dedicate this review to the memory of Dr. Claude Cr6tin, untimely deceased in August 1993. 1. Introductory remarks Phosphoenolpyruvate carboxylase (PEPC) catalyses the 'irreversible' /3-carboxylation of phosphoenolpyruvate (PEP) in the presence of 0168-9452/94/$07.00 © 1994 Elsevier Science Ireland Ltd. All rights reserved SSDI 0168-9452(94)03894-F