BRS1, a serine carboxypeptidase, regulates BRI1 signaling in Arabidopsis thaliana

Abstract

CorrectionsBIOCHEMISTRY. For the article ''Arg-302 facilitates deprotonation of Glu-325 in the transport mechanism of the lactose permease from Escherichia coli'' by Miklós Sahin-Tóth and H. Ronald Kaback, which appeared in number 11, May 22, 2001, of Proc. Natl. Acad. Sci. USA (98, 6068 -6073; First Published May 15, 2001; 10.1073͞pnas.111139698), Fig. 1 was printed incorrectly due to a printer's error. The correct figure and its legend appear below.www.pnas.org͞cgi͞doi͞10.1073͞pnas.151252598 Fig. 1.Model for H ϩ translocation during lactose͞H ϩ symport via lac permease. For clarity, 6 of the 12 helices that compose the permease are shown. The gray area designates the low dielectric environment of the lipid bilayer. (A) In the ground-state conformation, the relevant H ϩ is shared by His-322 (helix X) and Glu-269 (helix VIII), whereas Arg-302 (helix IX) is charge-paired with Glu-325 (helix X). In this conformation, lac permease binds substrate with high affinity at the outer surface (S o ). Glu-126 (helix IV) and Arg-144 (helix V) are charge-paired and represent the major components of the substrate-binding site. Also shown is the charge-pair between Asp-240 (helix VII) and Lys-319 (helix X), which are not essential for the mechanism. (B) Substrate binding induces a conformational change that disrupts the E269͞H322 and R302͞E325 charge-pairs and leads to the transfer of the H ϩ to Glu-325, now stabilized by the low dielectric environment. At the same time, the substrate-binding site becomes exposed to the inner surface of the membrane (S i ). After substrate dissociation, Glu-325 deprotonates at the inside surface (because of the rejuxtaposition of Glu-325 with Arg-302) as the permease relaxes back to the ground-state conformation.

An Expression and Bioinformatics Analysis of the Arabidopsis Serine Carboxypeptidase-Like Gene Family

“…This suggests that Arabidopsis SCPL proteins 22 to 46 act as genuine carboxypeptidases, although some members may be esterases or lyases (Degan et al, 1994;Wajant et al, 1994;Jones et al, 1996;Moura et al, 2001). Although its true substrate and the nature of its catalytic activity remain unknown, the finding that SCPL protein 24 is involved in brassinosteroid signaling suggest that Clade II members may play important roles in plant growth and development (Li et al, 2001a). Whatever the exact function of the Clade II SCPL proteins may be, the fact that they do not appear to be encoded within the genomes of animals and fungi suggests that these proteins have become specialized to perform functions that are likely to be unique to plants.…”

The brassinosteroid signal transduction pathway

“…In fact several lines of evidence supported the possibility that BRI1 might interact with another protein or peptide that binds directly to BR. For example, a secreted serine carboxypeptidase encoded by the BRS1 gene was shown to play an important role in the early stage of the BR signaling and was thus proposed to process an extracellular protein/peptide involved in BR perception [16]. Furthermore, there are at least two putative steroid-binding proteins (SBPs) in the Arabidopsis genome, raising the possibility that BR might bind a SBP that interacts directly with BRI1 [17].…”

Regulation ofArabidopsisBrassinosteroid Signaling by Atypical Basic Helix-Loop-Helix Proteins

“…Such an approach has been successful for identifying components of the BR signaling pathway, including BRS1 (Li et al, 2001b), BAK1 , BSU1 (Mora-Garcia et al, 2004), and BRL1 (Zhou et al, 2004). Here, we report that the Activation-Tagged Bri1-Suppressor1 (ATBS1) gene encodes an atypical 93-amino acid bHLH protein.…”