1. Phylogenetic and functional analyses of a plant protein related to human B-cell receptor-associated proteins.
- Author
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Atabekova AK, Pankratenko AV, Makarova SS, Lazareva EA, Owens RA, Solovyev AG, and Morozov SY
- Subjects
- Amino Acid Motifs genetics, Amino Acid Sequence, Electrophoresis, Polyacrylamide Gel, Escherichia coli genetics, Genome, Plant genetics, Humans, Membrane Proteins metabolism, MicroRNAs genetics, MicroRNAs metabolism, Multigene Family, Plant Leaves genetics, Plant Leaves metabolism, Plant Leaves virology, Plant Proteins classification, Plant Proteins metabolism, Plant Viruses genetics, Plant Viruses physiology, Protein Binding, RNA genetics, RNA metabolism, RNA, Viral genetics, RNA, Viral metabolism, Recombinant Proteins metabolism, Sequence Homology, Amino Acid, Solanum tuberosum virology, Nicotiana metabolism, Nicotiana virology, Viroids genetics, Viroids physiology, Membrane Proteins genetics, Phylogeny, Plant Proteins genetics, Nicotiana genetics
- Abstract
Human B-cell receptor-associated protein BAP31 (HsBAP31) is the endoplasmic reticulum-resident protein involved in protein sorting and transport as well as pro-apoptotic signaling. Plant orthologs of HsBAP31 termed 'plant BAP-like proteins' (PBL proteins) have thus far remained unstudied. Recently, the PBL protein from Nicotiana tabacum (NtPBL) was identified as an interactor of Nt-4/1, a plant protein known to interact with plant virus movement proteins and affect the long-distance transport of potato spindle tuber viroid (PSTVd) via the phloem. Here, we have compared the sequences of PBL proteins and studied the biochemical properties of NtPBL. Analysis of a number of fully sequenced plant genomes revealed that PBL-encoding genes represent a small multigene family with up to six members per genome. Two conserved motifs were identified in the C-terminal region of PBL proteins. The NtPBL C-terminal hydrophilic region (NtPBL-C) was expressed in bacterial cells, purified, and used for analysis of its RNA binding properties in vitro. In gel shift experiments, NtPBL-C was found to bind several tested RNAs, showing the most efficient binding to microRNA precursors (pre-miRNA) and less efficient interaction with PSTVd. Mutational analysis suggested that NtPBL-C has a composite RNA-binding site, with two conserved lysine residues in the most C-terminal protein region being involved in binding of pre-miRNA but not PSTVd RNA. Virus-mediated transient expression of NtPBL-C in plants resulted in stunting and leaf malformation, developmental abnormalities similar to those described previously for blockage of miRNA biogenesis/function. We hypothesize that the NtPBL protein represents a previously undiscovered component of the miRNA pathway., (Copyright © 2016 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.)
- Published
- 2017
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