Structural divergence of plant TCTPs

Abstract

The Translationally Controlled Tumor Protein (TCTP) is a highly conserved protein at the level of sequence, considered to play an essential role in the regulation of growth and development in eukaryotes. However, this function has been inferred from studies in a few model systems, such as mice and mammalian cell lines, Drosophila and Arabidopsis. Thus, the knowledge regarding this protein is far from complete. In the present study bioinformatic analysis showed the presence of one or more TCTP genes per genome in plants with highly conserved signatures and subtle variations at the level of primary structure but with more noticeable differences at the level of predicted three-dimensional structures. These structures show differences in the “pocket” region close to the center of the protein and in its flexible loop domain. In fact, all predictive TCTP structures can be divided into two groups: (1) AtTCTP1-like and (2) CmTCTP-like, based on the predicted structures of an Arabidopsis TCTP and a Cucurbita maxima TCTP; according to this classification we propose that their probable function in plants may be inferred in principle. Thus, different TCTP genes in a single organism may have different functions; additionally, in those species harboring a single TCTP gene this could carry multiple functions. On the other hand, in silico analysis of AtTCTP1-like and CmTCTP-like promoters suggest that these share common motifs but with different abundance, which may underscore differences in their gene expression patterns. Finally, the absence of TCTP genes in most chlorophytes with the exception of Coccomyxa subellipsoidea, indicates that other proteins perform the roles played by TCTP or the pathways regulated by TCTP occur through alternative routes. These findings provide insight into the evolution of this gene family in plants.

The Translational Controlled Tumour Protein TCTP: Biological Functions and Regulation

“…Typically, in these papers, a two-letter suffix before 'TCTP' indicates the species, from which the protein sequence was derived (see Gutierrez-Galeano et al (2014) for an example). The yeast orthologue of TCTP was named 'microtubule and mitochondria interacting protein' (Mmi1p) (Rinnerthaler et al 2006), but in another paper, it was also identified as the 'translation-machinery-associated protein 19' (TMA19) (Fleischer et al 2006), and yet the gene symbol in yeast is YKL056c.…”

“…Secondary structure elements are highlighted as follows: magenta: α-helices, yellow: β-sheets, blue lines: unstructured areas; major domains are indicated (from : Feng et al 2007a, PDB ID: 2HR9) A considerable number of 3D structures of other members of the TCTP family, in particular from various plant species, have been predicted (Gutierrez-Galeano et al 2014;Hinojosa-Moya et al 2008;Berkowitz et al 2008), based on the experimentally determined 3D-structures of TCTP and on sequence comparisons. Phylogenetic comparisons showed that the predicted tertiary structure of TCTP proteins is in general highly conserved throughout evolution (Gutierrez-Galeano et al 2014;Hinojosa-Moya et al 2008), although there are some deviations in the TCTP structure of lower eukaryotes (Hinojosa-Moya et al 2008) and some species of chlorophyta do not seem to have a TCTP gene at all (Gutierrez-Galeano et al 2014). In the plant kingdom, two principal types of TCTP structures are being distinguished, with some plants having the gene for one of the two types, whereas other ones have genes for both types (Gutierrez-Galeano et al 2014).…”

“…Phylogenetic comparisons showed that the predicted tertiary structure of TCTP proteins is in general highly conserved throughout evolution (Gutierrez-Galeano et al 2014;Hinojosa-Moya et al 2008), although there are some deviations in the TCTP structure of lower eukaryotes (Hinojosa-Moya et al 2008) and some species of chlorophyta do not seem to have a TCTP gene at all (Gutierrez-Galeano et al 2014). In the plant kingdom, two principal types of TCTP structures are being distinguished, with some plants having the gene for one of the two types, whereas other ones have genes for both types (Gutierrez-Galeano et al 2014).…”

1H, 15N and 13C resonance assignments of translationally-controlled tumor protein from photosynthetic microalga Nannochloropsis oceanica

“…Similar to mammalian TCTPs, plant TCTPs play important roles in cell growth, development, and anti-stress responses (Gutierrez-Galeano et al 2014). It has also been proposed that plant TCTP has functions specific to plant, such as the participation of photoperiodism, flowering, and auxin homeostasis (Gutierrez-Galeano et al 2014).…”

“…only a few of works have been reported about the function of TCTP in plants ( Gutierrez-Galeano et al 2014). Similar to mammalian TCTPs, plant TCTPs play important roles in cell growth, development, and anti-stress responses (Gutierrez-Galeano et al 2014).…”