TY - JOUR
T1 - The Evolutionarily Conserved Serine Residues in BRI1 LRR Motifs Are Critical for Protein Secretion
AU - Chen, Tianshu
AU - Wang, Bin
AU - Wang, Fangfang
AU - Niu, Guanting
AU - Zhang, Shuo
AU - Li, Jianming
AU - Hong, Zhi
N1 - Publisher Copyright:
© Copyright © 2020 Chen, Wang, Wang, Niu, Zhang, Li and Hong.
PY - 2020/2/6
Y1 - 2020/2/6
N2 - As a well-studied leucine-rich-repeat receptor-like kinases (LRR-RLKs) in Arabidopsis (Arabidopsis thaliana), BRI1 functions as a cell surface receptor for sensing the smallest ligand molecule identified thus far. The weak allele bri1-9 (S662F) harbors a mutation at the conserved serine (Ser*) residue among 25 LRRs, which leads to the protein retention in the ER. However, very little is known about the importance of these residues. Through site-directed mutagenesis and a phenotypic complementation test, we examined the effects of these conserved serine residues (S*-chain) on protein secretion and functions. The results showed that the replacements of these serine residues significantly changed the sub-localization of BRI1-GFPs to the ER and that rigid space constraints, as well as the requirement of successive inner polar contacts, affect these sites. In addition, the continuous presence of Ser* is mainly disrupted at the LRR-island domain interface, and the changes of these four nonserine residues to serine greatly decreased the protein ability to complement bri1-301 compact phenotype and the BR signaling activation. The sequence alignment revealed that other known LRR-RLK also harbors the S*-chain and the non-Ser* residues at the ligand-binding region along the S*-chain, which confirms the evolutionary significance of residues at these sites in plant LRR-RLKs.
AB - As a well-studied leucine-rich-repeat receptor-like kinases (LRR-RLKs) in Arabidopsis (Arabidopsis thaliana), BRI1 functions as a cell surface receptor for sensing the smallest ligand molecule identified thus far. The weak allele bri1-9 (S662F) harbors a mutation at the conserved serine (Ser*) residue among 25 LRRs, which leads to the protein retention in the ER. However, very little is known about the importance of these residues. Through site-directed mutagenesis and a phenotypic complementation test, we examined the effects of these conserved serine residues (S*-chain) on protein secretion and functions. The results showed that the replacements of these serine residues significantly changed the sub-localization of BRI1-GFPs to the ER and that rigid space constraints, as well as the requirement of successive inner polar contacts, affect these sites. In addition, the continuous presence of Ser* is mainly disrupted at the LRR-island domain interface, and the changes of these four nonserine residues to serine greatly decreased the protein ability to complement bri1-301 compact phenotype and the BR signaling activation. The sequence alignment revealed that other known LRR-RLK also harbors the S*-chain and the non-Ser* residues at the ligand-binding region along the S*-chain, which confirms the evolutionary significance of residues at these sites in plant LRR-RLKs.
KW - leucine-rich-repeat receptor-like kinases
KW - BRI1
KW - evolution
KW - Arabidopsis thaliana
KW - protein secretion
KW - BR signaling
UR - http://www.scopus.com/inward/record.url?scp=85079678770&partnerID=8YFLogxK
U2 - 10.3389/fpls.2020.00032
DO - 10.3389/fpls.2020.00032
M3 - Journal article
AN - SCOPUS:85079678770
SN - 1664-462X
VL - 11
JO - Frontiers in Plant Science
JF - Frontiers in Plant Science
M1 - 32
ER -