Sarnowska, E. | Search bioRxiv

bioRxiv2021

A Non-Canonical Function of Arabidopsis ERECTA Proteins in Gibberellin Signaling

The Arabidopsis ERECTA family (ERf) of leucine-rich repeat receptor-like kinases (LRR-RLKs), comprising ERECTA (ER), ERECTA-LIKE 1 (ERL1) and ERECTA-LIKE 2 (ERL2), control epidermal patterning, inflorescence architecture, stomata development, and hormonal signaling. Here we show that the er/erl1/erl2 triple mutant exhibits impaired gibberellin (GA) biosynthesis and perception alongside broad transcriptional changes. ERf proteins interact in the nucleus, via kinase domains, with the SWI3B subunit of the SWI/SNF chromatin remodeling complex (CRCs). The er/erl1/erl2 triple mutant exhibits reduced SWI3B protein level and affected nucleosomal chromatin structure. The ER kinase phosphorylates SWI3B in vitro, and the inactivation of all ERf proteins leads to the decreased phosphorylation of SWI3B protein in vivo. Correlation between DELLA overaccumulation and SWI3B proteasomal degradation together with the physical interaction of SWI3B with DELLA proteins explain the lack of RGA accumulation in the GA- and SWI3B-deficient erf mutant plants. Co-localization of ER and SWI3B on GID1 (GIBBERELLIN INSENSITIVE DWARF 1) DELLA target gene promoter regions and abolished SWI3B binding to GID1 promoters in er/erl1/erl2 plants supports the conclusion that ERf-SWI/SNF CRC interaction is important for transcriptional control of GA receptors. Thus, the involvement of ERf proteins in transcriptional control of gene expression, and observed similar features for human HER2 (Epidermal Growth Family Receptor-member), indicate an exciting target for further studies of evolutionarily conserved non-canonical functions of eukaryotic membrane receptors. ONE SENTENCE SUMMARYERECTA leucine-rich receptor-like kinase and SWI3B subunit of SWI/SNF chromatin remodeling complex cooperate in direct transcriptional control of GID1 genes in Arabidopsis.

plant biology↗

bioRxiv2020

Common low complexity regions for SARS-CoV-2 and human proteomes as potential multidirectional risk factor in vaccine development

The rapid spread of the COVID-19 demands immediate response from the scientific communities. Appropriate countermeasures mean thoughtful and educated choice of viral targets (epitopes). There are several articles that discuss such choices in the SARS-CoV-2 proteome, other focus on phylogenetic traits and history of the Coronaviridae genome/proteome. However none consider viral protein low complexity regions (LCRs). Recently we created the first methods that are able to compare such fragments. We show that five low complexity regions (LCRs) in three proteins (nsp3, S and N) encoded by the SARS-CoV-2 genome are highly similar to regions from human proteome. As many as 21 predicted T-cell epitopes and 27 predicted B-cell epitopes overlap with the five SARS-CoV-2 LCRs similar to human proteins. Interestingly, replication proteins encoded in the central part of viral RNA are devoid of LCRs. Similarity of SARS-CoV-2 LCRs to human proteins may have implications on the ability of the virus to counteract immune defenses. The vaccine targeted LCRs may potentially be ineffective or alternatively lead to autoimmune diseases development. These findings are crucial to the process of selection of new epitopes for drugs or vaccines which should omit such regions. Author summaryThe outbreak of the COVID-19 disease affects humans all over the globe. More and more people get sick and many die because of the deadly SARS-CoV-2 virus. The whole machinery of this pathogen is enclosed in a short sequence of nucleotides, building blocks for both RNA and DNA strands. This RNA virus encodes less than 30 protein sequences that change the fate of our societies. Its proteins are composed of 20 amino acids (building bricks) that are usually used quite freely by proteins. However, there are fragments where only one or a few amino acids are used. We name those low complexity regions (LCRs). We invented the first programmes able to compare such LCRs. Using this new methodology we were able to show similarity of some viral proteins to human ones. This discovery has a serious implication when designing vaccines or drugs. It means that companies should not use these very LCRs as targets because it may trigger an autoimmune disease. On the other hand this specific similarity may suggest some kind of disguise of viral proteins into the machinery of human cells.

bioinformatics↗