Related Experiment Video
Updated: Nov 10, 2025

Identification of Plasmodesmal Localization Sequences in Proteins In Planta
Published on: August 15, 2017
Structural features of the plant N-recognin ClpS1 and sequence determinants in its targets that govern substrate
Dianela Aguilar Lucero1, Alejo Cantoia1, Carolina Sánchez-López1
1CONICET, Facultad de Ciencias Bioquímicas y Farmacéuticas, Instituto de Biología Molecular y Celular de Rosario (IBR), Universidad Nacional de Rosario, Argentina.
Abstract:
In the N-degron pathway of protein degradation of Escherichia coli, the N-recognin ClpS identifies substrates bearing N-terminal phenylalanine, tyrosine, tryptophan, or leucine and delivers them to the caseinolytic protease (Clp). Chloroplasts contain the Clp system, but whether chloroplastic ClpS1 adheres to the same constraints is unknown. Moreover, the structural underpinnings of substrate recognition are not completely defined. We show that ClpS1 recognizes canonical residues of the E. coli N-degron pathway. The residue in second position influences recognition (especially in N-terminal ends starting with leucine). N-terminal acetylation abrogates recognition. ClpF, a ClpS1-interacting partner, does not alter its specificity. Substrate binding provokes local remodeling of residues in the substrate-binding cavity of ClpS1. Our work strongly supports the existence of a chloroplastic N-degron pathway.
Related Concept Videos
Regulation of Nuclear Protein Sorting
Cell Signaling in Plants
Nuclear Localization Signals and Import
Nuclear Protein Sorting
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Protein Transport to the Inner Chloroplast Membrane
Conserved Binding Sites
Binding sites are often located in large pockets, and if their location on a protein’s surface is unknown, it can be predicted using various approaches. The energetic method computationally...

