Steven C. Huber

Steven C. Huber
United States Department of Agriculture | USDA · Global Change and Photosynthesis Research Unit

About

315
Publications
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18,619
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Publications

Publications (315)
Article
Full-text available
Calcium (Ca ²⁺ )-dependent protein kinases (CDPKs or CPKs) are a unique family of Ca ²⁺ sensor/kinase-effector proteins with diverse functions in plants. In Arabidopsis thaliana , CPK28 contributes to immune homeostasis by promoting degradation of the key immune signaling receptor-like cytoplasmic kinase BOTRYTIS-INDUCED KINASE 1 (BIK1) and additio...
Preprint
Full-text available
Calcium (Ca ²⁺ )-dependent protein kinases (CDPKs or CPKs) are a unique family of Ca ²⁺ -sensor/kinase-effector proteins with diverse functions in plants. In Arabidopsis thaliana , CPK28 contributes to immune homeostasis by promoting degradation of the key immune signaling receptor-like cytoplasmic kinase BOTRYTIS-INDUCED KINASE 1 (BIK1), and addit...
Article
Rubisco activase (Rca) facilitates the release of sugar‐phosphate inhibitors from the active sites of Rubisco and thereby plays a central role in initiating and sustaining Rubisco activation. In Arabidopsis, alternative splicing of a single Rca gene results in two Rca isoforms, Rca‐α and Rca‐β. Redox modulation of Rca‐α regulates the function of Rc...
Article
Arabidopsis Rubisco activase (Rca) is phosphorylated at threonine-78 (Thr78) in low light and in the dark, suggesting a potential regulatory role in photosynthesis, but this has not been directly tested. To do so, we transformed an rca -knockdown mutant largely lacking redox regulation with wild-type Rca-β or Rca-β with Thr78-to-Ala (T78A) or Thr78...
Article
Full-text available
Tyrosine phosphorylation has emerged as an important regulator of plasma membrane-localized immune receptors activity. Here, we investigate the role of tyrosine phosphorylation in the regulation of rice XANTHOMONAS RESISTANCE 21 (XA21)-mediated immunity. We demonstrate that the juxtamembrane and kinase domain of Escherichia coli –expressed XA21 (XA...
Article
Full-text available
Calcium (Ca2+) serves as a universal second messenger in eukaryotic signal transduction. Understanding the Ca2+ activation kinetics of Ca2+ sensors is critical to understanding the cellular signaling mechanisms involved. In this review, we discuss the regulatory properties of two sensor classes: the Ca2+-dependent protein kinases (CPKs/CDPKs) and t...
Article
Growing evidence supports the importance of protein S-glutathionylation as a regulatory post-translational modification with functional consequences for proteins. Discoveries of redox-state-dependent protein kinase S-glutathionylation have fueled discussion of redox-sensitive signaling. Following previously published experimental evidence for S-glu...
Article
Full-text available
The plasma membrane-localized BRI1-ASSOCIATED KINASE1 (BAK1) functions as a co-receptor with several receptor kinases including the brassinosteroid (BR) receptor BRASSINOSTEROID-INSENSITIVE 1 (BRI1), which is involved in growth, and the receptors for bacterial flagellin and EF-Tu, FLAGELLIN-SENSING 2 (FLS2) and EF-TU RECEPTOR (EFR), respectively, w...
Article
Full-text available
The structural motifs responsible for activation and regulation of eukaryotic protein kinases in animals have been studied extensively in recent years, and a coherent picture of their activation mechanisms has begun to emerge. On the other hand, non-animal eukaryotic protein kinases are not as well understood from a structural perspective, represen...
Article
Full-text available
Irradiance continuously fluctuates during the day in the field. The speed of the induction response of photosynthesis in high light affects the cumulative carbon gain of the plant and could impact growth and yield. The photosynthetic induction response and its relationship with the photosynthetic capacity under steady-state conditions (P max) were...
Article
Full-text available
Plant calcium (Ca2+) dependent protein kinases (CPKs) represent the primary Ca2+-dependent protein kinase activities in plant systems. CPKs are composed of a dual specificity (Ser/Thr and Tyr) kinase domain tethered to a Calmodulin-like domain (CLD) via an autoinhibitory junction (J). While regulation of CPKs by Ca2+ has been extensively studied, t...
Article
Full-text available
Although soybean seeds appear homogeneous, their composition (protein, oil and mineral concentrations) can vary significantly with the canopy position where they were produced. In studies with 10 cultivars grown over a 3-yr period, we found that seeds produced at the top of the canopy have higher concentrations of protein but less oil and lower con...
Data
Interactive Correlation plots of all plot normalized data
Data
Interactive Correlation plots of plot mean data
Data
Interactive Correlation plots of all data, not normalized
Data
Weather summary (June 1?August 31) during the 2010 to 2012 growing seasons
Data
Raw Gradient plots for each line/year combination Values are PPM (Elements), mg (SampleWeight), and Percentage (Protein/Oil).
Data
Analysis of metabolome of developing soybean seeds (A) PLS-DA scores plot (R2 = 98.7%, Q2 = 81.1%, P < 0.001 by permutation test) of soybean seeds at different canopy position and time of day. (B) Variable Importance in the Projection (VIP) for the first component showing the fifteen most important compounds.
Data
Indeterminate lines used in the present study and selected characteristics
Data
All Compositional Traits Normalized Gradients
Data
Composiition of food products for all elements
Data
Genotype differences in Seed fill period (SFP) and the difference in SFP at two node positions (bottom minus top; delSFP)
Poster
BRASSINOSTEROID INSENSITIVE1 (BRI1) serves as a model for elucidating the mechanisms underlying the interplay between receptor trafficking and signal transduction. BRI1 internalization was recognized as being ligand-independent and constitutive. But, we found that the residency time of BRI1-lablled foci in the plasma membrane (PM) is ligand-depende...
Preprint
Full-text available
Although soybean seeds appear homogeneous, their composition (protein, oil and mineral concentrations) can vary significantly with the canopy position where they were produced. In studies with 10 cultivars grown over a 3-yr period, we found that seeds produced at the top of the canopy have higher concentrations of protein but less oil and lower con...
Article
Full-text available
Rubisco activase (RCA) is essential for the activation of Rubisco, the carboxylating enzyme of photosynthesis. In Arabidopsis, RCA is composed of a large RCAα and small RCAβ isoform that are formed by alternative splicing of a single gene (At2g39730). The activity of Rubisco is controlled in response to changes in irradiance by regulation of RCA ac...
Data
Full panels of the trimmed immunoblots presented in Figure 1A showing the specificity of the anti-RCA (A) and anti-pT78 (B) antibodies used in this study. The off-target band (marked with the asterisk) that migrates just above the Rubisco large subunit (RbcL) protein and reacts with the anti-pT78 antibodies provides a useful loading control.
Data
Full panel of the trimmed immunoblot presented in Figure 2 showing that no inter-subunit disulfide bonds with RCAα were apparent when non-reducing SDS-PAGE gels were used to fractionate proteins prior to immunoblot analysis. The blot was intentionally visualized at a higher sensitivity than used in Figure 2 to help distinguish any low abundance, hi...
Article
Full-text available
The relationship between asparagine metabolism and protein concentration was investigated in soybean seed. Phenotyping of a population of recombinant inbred lines adapted to Illinois confirmed a positive correlation between free asparagine levels in developing seeds and protein concentration at maturity. Analysis of a second population of recombina...
Article
Full-text available
BRI1 becomes highly phosphorylated in vivo upon perception of the ligand, brassinolide, as a result of autophosphorylation and transphosphorylation by its co-receptor kinase, BAK1. Important autophosphorylation sites include those involved in activation of kinase activity and those that are inhibitory, such as Ser-891. The inhibitory sites are auto...
Article
Leucine-rich repeat receptor-like kinases (LRR RLKs) form a large family of plant signaling proteins consisting of an extracellular domain connected by a single-pass transmembrane sequence to a cytoplasmic kinase domain. Autophosphorylation on specific Ser and/or Thr residues in the cytoplasmic domain is often critical for the activation of several...
Article
Full-text available
Reversible protein phosphorylation, catalyzed by protein kinases, is the most widely studied post-translational modification whereas the analysis of other modifications such as S-thiolation is in its relative infancy. In a yeast-two-hybrid (Y2H) screen, we identified a number of novel putative BRASSINOSTEROID INSENSITIVE 1-ASSOCIATED RECEPTOR-LIKE...
Article
Full-text available
Sugarcane is a monocot plant that accumulates sucrose to levels of up to 50% of dry weight in the stalk. The mechanisms that are involved in sucrose accumulation in sugarcane are not well understood, and little is known with regard to factors that control the extent of sucrose storage in the stalks. UDP-glucose pyrophosphorylase (UGPase; EC 2.7.7.9...
Article
Full-text available
Postemergence (POST) application of 4-hydroxyphenyl pyruvate dioxygenase (HPPD) inhibitors in combination with a photosystem II (PSII) inhibitor, such as atrazine [6-chloro-N-ethyl-N9-(1-methylethyl)-1,3,5-triazine-2,4-diamine], is common practice in sweet corn (Zea mays L.) production. Given the sensitivity of sweet corn to HPPD-inhibiting herbici...
Article
Full-text available
Innate immunity relies on the perception of pathogen-associated molecular patterns (PAMPs) by pattern-recognition receptors (PRRs) located on the host cell's surface. Many plant PRRs are kinases. Here, we report that the Arabidopsis receptor kinase EF-TU RECEPTOR EFR, which perceives the elf18 peptide derived from bacterial elongation factor Tu, is...
Article
Full-text available
Binding of brassinolide to the brassinosteroid-insenstive 1(BRI1) receptor kinase promotes interaction with its co-receptor, BRI1-associated receptor kinase 1 (BAK1). Juxtaposition of the kinase domains that occurs then allows reciprocal transphosphorylation and activation of both kinases, but details of that process are not entirely clear. In the...
Article
Full-text available
Several plant CDPKs were recently shown to be dual specificity kinases rather than Ser/Thr kinases as traditionally classified by sequence analysis. In the present study we confirm the autophosphorylation of recombinant soybean His 6-GmCDPKβ at the Tyr-24 site using sequence- and modification- specific antibodies. Homology modeling of soybean CDPKβ...
Article
Full-text available
Brassinosteroids (BRs) are essential plant hormones that are perceived at the cell surface by a membrane bound receptor kinase, BRASSINOSTEROID INSENSITIVE 1 (BRI1). BRI1 interacts with BRI1-ASSOCIATED RECEPTOR KINASE 1 (BAK1) to initiate a signal transduction pathway in which autophosphorylation and transphosphorylation of BRI1 and BAK1, as well a...
Article
Protein lysine acetylation (LysAc) has recently been demonstrated to be widespread in E. coli and Salmonella, and to broadly regulate bacterial physiology and metabolism. However, LysAc in plant pathogenic bacteria is largely unknown. Here we first report the lysine acetylome of Erwinia amylovora, an enterobacterium causing serious fire blight dise...
Article
Full-text available
Protein kinase specificity is of fundamental importance to pathway regulation and signal transduction. Here, we report a convenient system to monitor the activity and specificity of recombinant protein kinases expressed in E. coli. We apply this to the study of the cytoplasmic domain of the plant receptor kinase BRASSINOSTEROID-INSENSITIVE 1 (BRI1)...
Data
Identification of transphosphorylation sites of E. coli proteins mediated by BRI1, BAK1, PEPR1, CDPKβ, or FLS2. Tryptic peptides containing phosphorylated residues (pS or pT) are listed along with the experimental (expt) and calculated (calc) monoisotopic masses and the expectation value (expect) reported in Mascot. The values for spectral counts f...
Article
Although calcium-dependent protein kinases (CDPKs or CPKs) are classified as serine/threonine protein kinases, autophosphorylation on tyrosine residues was observed for soybean CDPKβ and several Arabidopsis isoforms (AtCPK4 and AtCPK34). We identified Ser-8, Thr-17, Tyr-24 (in the kinase domain), Ser-304, and Ser-358 as autophosphorylation sites of...
Article
Full-text available
The soybean (Glycine max L. Merr.) genome contains 18 members of the 14-3-3 protein family, but little is known about their association with specific phenotypes. Here, we report that the Glyma0529080 (SGF14c) and Glyma08g12220 (SGF14l) genes, encoding 14-3-3 proteins, appear to play essential roles in soybean nodulation. QRT-PCR and western immunob...
Article
Full-text available
In metazoans, receptor kinases control many essential processes related to growth and development and response to the environment. The receptor kinases in plants and animals are structurally similar but evolutionarily distinct and thus while most animal receptor kinases are tyrosine kinases the plant receptor kinases are classified as serine/threon...
Article
Full-text available
The relationship between asparagine metabolism and protein concentration was investigated in soybean seed. Phenotyping of a population of recombinant inbred lines adapted to Illinois confirmed a positive correlation between free asparagine levels in developing seeds and protein concentration at maturity. Analysis of a second population of recombina...
Article
Full-text available
The receptor kinase BRI1 (BRASSINOSTEROID-INSENSITIVE 1) is a key component in BR (brassinosteroid) perception and signal transduction, and has a broad impact on plant growth and development. In the present study, we demonstrate that Arabidopsis CaM (calmodulin) binds to the recombinant cytoplasmic domain of BRI1 in a Ca2+-dependent manner in vitro...
Article
Full-text available
The soybean (Glycine max) genome contains 18 members of the 14-3-3 protein family, but little is known about their association with specific phenotypes. Here, we report that the Glyma0529080 Soybean G-box Factor 14-3-3c (SGF14c) and Glyma08g12220 (SGF14l) genes, encoding 14-3-3 proteins, appear to play essential roles in soybean nodulation. Quantit...
Article
Full-text available
Plant genomes encode hundreds of receptor-like kinases (RLKs) with an organization of functional domains similar to those of animal receptor kinases. Ligand-dependent phosphorylation has now been demonstrated for several plant RLKs and identification of specific phosphorylation sites followed by their func-tional characterization has advanced our u...
Article
Full-text available
The activity of the dual-specificity receptor kinase, brassinosteroid insensitive 1 (BRI1), reflects the balance between phosphorylation-dependent activation and several potential mechanisms for deactivation of the receptor. In the present report, we elucidate a unique mechanism for deactivation that involves autophosphorylation of serine-891 in th...
Data
Amino acid sequence alignments of YbjN homologs from seven enterobacterial strains. Deduced amino acid sequences have been obtained from NCBI and aligned by ClustalW program (www.ebi.ac.uk/Tools/clustalw2). Identical residues (*), conserved (:) and semi-conserved (.) substitutions are shown as underneath symbols. Gaps introduced for alignment are i...