Research Progress on Plant RING-Finger Proteins

Abstract

E3 ubiquitin ligases are the most expanded components of the ubiquitin proteasome system (UPS). They mediate the recognition of substrates and later transfer the ubiquitin (Ub) of the system. Really Interesting New Gene (RING) finger proteins characterized by the RING domain, which contains 40-60 residues, are thought to be E3 ubiquitin ligase. RING-finger proteins play significant roles in plant growth, stress resistance, and signal transduction. In this study, we mainly describe the structural characteristics, classifications, and subcellular localizations of RING-finger proteins, as well the physiological processes of RING-finger proteins in plant growth and development. We also summarize the functions of plant RING-finger proteins in plant stress resistance. Finally, further research on plant RING-finger proteins is suggested, thereby establishing a strong foundation for the future study of plant RING-finger proteins.

Keywords: RING-finger proteins; adversity stress; plant development.

Figure 1

The cross structure between Really Interesting New Gene (RING)-finger protein sequences [9]. The circle represents the cysteine (Cys) and histidine (His) residue; the pentagonal form represents the bound Zn²⁺; the connecting line represents the minimum and maximum range of the number of linked amino acids; N represents the N-terminus, C represents the C-terminus, Cys1 represents ML, and Cys1 and Cys2 together with Cys5 and Cys6 bind the first Zn²⁺, whereas Cys3 and Cys4 together with Cys7 and Cys8 bind the second Zn²⁺.

Figure 2

The structure diagram of different RING-finger domains. (A) RING-H2; (B), RING-HC; (C) RING-C2; (D), RING-v; (E) RING-D; (F) RING-S/T; (G) RING-G; N represents the N-terminus, C represents the C-terminus; 1–8 represent the ML, the blue circle represents the Cys amino acid residue, the dark green circle represents the Asp amino acid residue, the red circle represents the Gly amino acid residue, the light green circle represents the His amino acid residue, the purple circle represents the Ser/Thr amino acid residue, and and the yellow circle represents the Cys/Ser. The shape pentagons represent the Zn+; the red letter represents the conserved amino acid residue, and X stands for any amino acid.