Molecular insights into the function of ankyrin proteins in plants

Abstract

Ankyrin (ANK) repeat domain-containing proteins comprise one of the largest known protein superfamilies in all species including plants. Recently, several genomeanalysis studies have provided valuable information on the structure of ANK proteins in plants. Among the 13 subgroups based on the presence of various additional domains in addition to the ANK domain, the E3 ubiquitin ligase activity and transcriptional regulation functions of ANK-RF and ANK-ZF subgroup members, respectively, are relatively well understood. NPR1 (nonexpressor of pathogenesis-related1), a key regulator of systemic acquired resistance in Arabidopsis, is a noteworthy member of the ANK-BTB subgroup; however, ANK-M and ANK-TM, the two main subgroups, have been less functionally characterized. With the ability to mediate protein-protein interactions, the majority of plant ANK proteins play crucial roles in defense responses and, on occasion, functions in growth and development. In this review, we summarize on the current knowledge of plant ANK superfamily members and focus on ANK proteins involved in defense responses. In addition, we provide a valuable framework for the future functional characterization of ANK genes with current unknown function in rice, a model crop species.

The ankyrin repeat gene family in Capsicum spp: Genome-wide survey, characterization and gene expression profile

“…ANK repeats contain a ~33-residue motif repeated in tandem and consisting of two antiparallel α-helices connected by a series of inverting β-hairpin motifs. Indeed, the ANK domain is better characterized by a folding structure rather than functional requirements 5,6 . Although the ANK domain proteins are not known to have a specific function, they play important roles in several biological activities and have been identified in abundant different proteins with diverse functions 7 .…”

“…ANK proteins reported in plants are classified into 13 subfamilies based on different domains that have been identified by genome structure studies and gene expression profiles 6 . ANK domain-containing proteins of plants are usually involved in crucial physiological and developmental processes such as signaling and growth 11 , plastid differentiation 12 , embryogenesis 13 , chloroplast biogenesis 14 , formation of grana 15 , leaf morphogenesis 16 , pollen germination and polarized pollen tube growth 17,18 .…”

Silencing of a unique integrated domain nucleotide-binding leucine-rich repeat gene in wheat abolishesDiuraphis noxiaresistance

“…Proteins contain one to 33 repeats, although at least two repeats are necessary in order to assume a folded structure (Leila et al 2004). In plants, ankyrin domain-containing proteins are involved in a wide variety of biological processes with the majority linked to defense responses (Vo et al 2015). Observations of ankyrin protein-protein interactions involved in plant defense show that they bind and perceive effectors in the plasma membrane, cytosolic signal transduction and activation of nuclear defense gene expression, depending on the subcellular localization signal of the ankyrin repeat domain-containing protein (Vo et al 2015).…”

“…A small number of proteins may have a Solanaceae domain or a BED DNA binding domain replacing or in conjunction with the CC-domain (Collier and Moffett 2009). Ankyrin repeat domain-containing proteins constitute one of the largest protein families in all species and plays a role in protein recognition and binding (Mosavi et al 2004; Vo et al 2015). Proteins contain one to 33 repeats, although at least two repeats are necessary in order to assume a folded structure (Leila et al 2004).…”

“…In plants, ankyrin domain-containing proteins are involved in a wide variety of biological processes with the majority linked to defense responses (Vo et al 2015). Observations of ankyrin protein-protein interactions involved in plant defense show that they bind and perceive effectors in the plasma membrane, cytosolic signal transduction and activation of nuclear defense gene expression, depending on the subcellular localization signal of the ankyrin repeat domain-containing protein (Vo et al 2015). In the case of 5AL-B4 , the ankyrin repeats may mediate intermolecular interactions, where they bind proteins involved in the defense gene cascade once the effector has been detected by the WRKY motif and the receptor has been activated.…”