Multifarious Roles of Intrinsic Disorder in Proteins Illustrate Its Broad Impact on Plant Biology

Abstract

Intrinsically disordered proteins (IDPs) are highly abundant in eukaryotic proteomes. Plant IDPs play critical roles in plant biology and often act as integrators of signals from multiple plant regulatory and environmental inputs. Binding promiscuity and plasticity allow IDPs to interact with multiple partners in protein interaction networks and provide important functional advantages in molecular recognition through transient protein-protein interactions. Short interaction-prone segments within IDPs, termed molecular recognition features, represent potential binding sites that can undergo disorder-to-order transition upon binding to their partners. In this review, we summarize the evidence for the importance of IDPs in plant biology and evaluate the functions associated with intrinsic disorder in five different types of plant protein families experimentally confirmed as IDPs. Functional studies of these proteins illustrate the broad impact of disorder on many areas of plant biology, including abiotic stress, transcriptional regulation, light perception, and development. Based on the roles of disorder in the protein-protein interactions, we propose various modes of action for plant IDPs that may provide insight for future experimental approaches aimed at understanding the molecular basis of protein function within important plant pathways.

The Unstructured N-terminal Region of Arabidopsis Group 4 Late Embryogenesis Abundant (LEA) Proteins Is Required for Folding and for Chaperone-like Activity under Water Deficit

“…The composition of these proteins is also characteristic of a group of proteins known as intrinsically disordered proteins (IDPs) (5,6). Consistent with the predicted structural disorder for most LEA proteins, structural analyses have confirmed this property for some of them in aqueous solution (7)(8)(9)(10)(11)(12)(13). Based on their sequence similarity, LEA proteins have been classified in seven groups or families, each one characterized by the presence of specific sequence motifs (2).…”

“…domains are highly abundant in eukaryotic proteomes and perform important functions (6). In plants, IDPs participate in developmental control, light perception, transcriptional regulation, and response to abiotic stress (12). LEA proteins are the plant protein family with the highest number of proteins either predicted or characterized as IDPs (12).…”

“…1A). Because of the amino acid composition of this group of LEA proteins, it was proposed that they are IDPs (2,12). In silico analyses using PONDR (VLXT) (34) (Fig.…”

Pipeline to Identify Hydroxyproline-Rich Glycoproteins

“…Features of other IDPs can be incorporated into MAAB and used to identify IDPs in available genomes/transcriptomes. This would allow the identification of, for example, the repetitive domains of elastins (Roberts et al, 2015), salivary PRPs (Manconi et al, 2016), insect silks (Starrett et al, 2012), AGL proteins from arbuscular mycorrhizal fungi (Schultz and Harrison, 2008), and LATE EMBRYOGENESIS ABUNDANT proteins in plants (Sun et al, 2013), with low rates of false negatives and false positives.…”

“…In plants, IDPs are implicated in stress responses, signaling, and molecular recognition pathways (Pietrosemoli et al, 2013;Sun et al, 2013). As plants are sessile, IDPs related to environmental stress responses are proposed to be particularly critical to enable adaptation to challenging environments (Gomord et al, 2010;Pietrosemoli et al, 2013;Kurotani and Sakurai, 2015).…”