@article{shen_hanley-bowdoin_2021, title={SnRK1: a versatile plant protein kinase that limits geminivirus infection}, volume={47}, ISSN={["1879-6265"]}, DOI={10.1016/j.coviro.2020.12.002}, abstractNote={Geminiviruses are a family of single-stranded DNA viruses that infect many plant species and cause serious diseases in important crops. The plant protein kinase, SnRK1, has been implicated in host defenses against geminiviruses. Overexpression of SnRK1 makes plants more resistant to geminivirus infection, and knock-down of SnRK1 increases susceptibility to geminivirus infection. GRIK, the SnRK1 activating kinase, is upregulated by geminivirus infection, while the viral C2 protein inhibits the SnRK1 activity. SnRK1 also directly phosphorylates geminivirus proteins to reduce infection. These data suggest that SnRK1 is involved in the co-evolution of plant hosts and geminiviruses.}, journal={CURRENT OPINION IN VIROLOGY}, author={Shen, Wei and Hanley-Bowdoin, Linda}, year={2021}, month={Apr}, pages={18–24} }
 @article{caldo_shen_xu_hanley-bowdoin_chen_weselake_lemieux_2018, title={Diacylglycerol acyltransferase 1 is activated by phosphatidate and inhibited by SnRK1-catalyzed phosphorylation}, volume={96}, ISSN={["1365-313X"]}, DOI={10.1111/tpj.14029}, abstractNote={Summary}, number={2}, journal={PLANT JOURNAL}, author={Caldo, Kristian Mark P. and Shen, Wei and Xu, Yang and Hanley-Bowdoin, Linda and Chen, Guanqun and Weselake, Randall J. and Lemieux, M. Joanne}, year={2018}, month={Oct}, pages={287–299} }
 @article{shen_bobay_greeley_reyes_rajabu_blackburn_dallas_goshe_ascencio-ibanez_hanley-bowdoin_2018, title={Sucrose Nonfermenting 1-Related Protein Kinase 1 Phosphorylates a Geminivirus Rep Protein to Impair Viral Replication and Infection}, volume={178}, ISSN={["1532-2548"]}, DOI={10.1104/pp.18.00268}, abstractNote={Sucrose nonfermenting 1-related protein kinase 1 targets the geminivirus Rep protein to interfere with viral infection. Geminiviruses are single-stranded DNA viruses that infect a wide variety of plants and cause severe crop losses worldwide. The geminivirus replication initiator protein (Rep) binds to the viral replication origin and catalyzes DNA cleavage and ligation to initiate rolling circle replication. In this study, we found that the Tomato golden mosaic virus (TGMV) Rep is phosphorylated at serine-97 by sucrose nonfermenting 1-related protein kinase 1 (SnRK1), a master regulator of plant energy homeostasis and metabolism. Phosphorylation of Rep or the phosphomimic S97D mutation impaired Rep binding to viral DNA. A TGMV DNA-A replicon containing the Rep S97D mutation replicated less efficiently in tobacco (Nicotiana tabacum) protoplasts than in wild-type or Rep phosphorylation-deficient replicons. The TGMV Rep-S97D mutant also was less infectious than the wild-type virus in Nicotiana benthamiana and was unable to infect tomato (Solanum lycopersicum). Nearly all geminivirus Rep proteins have a serine residue at the position equivalent to TGMV Rep serine-97. SnRK1 phosphorylated the equivalent serines in the Rep proteins of Tomato mottle virus and Tomato yellow leaf curl virus and reduced DNA binding, suggesting that SnRK1 plays a key role in combating geminivirus infection. These results established that SnRK1 phosphorylates Rep and interferes with geminivirus replication and infection, underscoring the emerging role for SnRK1 in the host defense response against plant pathogens.}, number={1}, journal={PLANT PHYSIOLOGY}, author={Shen, Wei and Bobay, Benjamin G. and Greeley, Laura A. and Reyes, Maria I. and Rajabu, Cyprian A. and Blackburn, R. Kevin and Dallas, Mary Beth and Goshe, Michael B. and Ascencio-Ibanez, Jose T. and Hanley-Bowdoin, Linda}, year={2018}, month={Sep}, pages={372–389} }
 @article{shen_dallas_goshe_hanley-bowdoin_2014, title={SnRK1 Phosphorylation of AL2 Delays Cabbage Leaf Curl Virus Infection in Arabidopsis}, volume={88}, ISSN={["1098-5514"]}, DOI={10.1128/jvi.00761-14}, abstractNote={ABSTRACT}, number={18}, journal={JOURNAL OF VIROLOGY}, author={Shen, Wei and Dallas, Mary Beth and Goshe, Michael B. and Hanley-Bowdoin, Linda}, year={2014}, month={Sep}, pages={10598–10612} }
 @article{shen_reyes_hanley-bowdoin_2009, title={Arabidopsis Protein Kinases GRIK1 and GRIK2 Specifically Activate SnRK1 by Phosphorylating Its Activation Loop}, volume={150}, ISSN={["1532-2548"]}, DOI={10.1104/pp.108.132787}, abstractNote={Abstract}, number={2}, journal={PLANT PHYSIOLOGY}, author={Shen, Wei and Reyes, Maria Ines and Hanley-Bowdoin, Linda}, year={2009}, month={Jun}, pages={996–1005} }
 @article{oh_huber_shen_athwal_wu_huber_2009, title={Overexpression of a directed mutant of 14-3-3 omega in Arabidopsis leaves affects phosphorylation and protein content of nitrate reductase}, volume={87}, ISSN={["1916-2804"]}, DOI={10.1139/b09-003}, abstractNote={ The 14-3-3 family of proteins are highly conserved signaling proteins in eukaryotes that bind to their client proteins, usually through specific phosphorylated target sequences. While the 14-3-3 proteins are thought to interact with a wide array of cellular proteins, there have been few studies addressing the in-vivo role of 14-3-3. As one approach to study this in-vivo role, we generated transgenic Arabidopsis plants constitutively overexpressing a directed mutant of 14-3-3 isoform ω that inhibits phosphorylated nitrate reductase (pNR) in a largely divalent-cation-independent manner in vitro. The transgenic plants had increased relative phosphorylation of NR at the regulatory Ser-534 site and decreased NR activity measured in the presence of 5 mmol·L–1 MgCl2 relative to nontransgenic plants. In addition, total NR protein was increased and the protein half-life was increased about two-fold. Two-dimensional difference gel electrophoresis analysis of proteins extracted from leaves of plants expressing the mutant 14-3-3 identified numerous cellular proteins that were altered in abundance. In particular, several β-glucosidase and glutathione S-transferase isoforms were decreased in abundance relative to wild type plants suggesting a possible alteration in stress or defense responses. }, number={7}, journal={BOTANY}, author={Oh, Man-Ho and Huber, Joan L. and Shen, Wei and Athwal, Gurdeep S. and Wu, Xia and Huber, Steven C.}, year={2009}, month={Jul}, pages={691–701} }
 @article{jordan_shen_hanley-bowdoin_robertson_2007, title={Geminivirus-induced gene silencing of the tobacco retinoblastoma-related gene results in cell death and altered development}, volume={65}, ISSN={["1573-5028"]}, DOI={10.1007/s11103-007-9206-3}, abstractNote={The retinoblastoma-related protein (RBR) is required for cell cycle control and differentiation and is expressed throughout the life of plants and animals. In this study, the tomato golden mosaic virus (TGMV) geminivirus vector was used to silence NbRBR1 in Nicotiana benthamiana by microprojectile bombardment into fully developed leaves. Similar to previous results using agroinoculation of a tobacco rattle virus silencing vector [Park et al. (Plant J 42:153, 2005)], developmental defects caused by disruptions in cell size and number were seen in new growth. Leaf midvein cross-sections showed tissue-specific differences in size, cell number, and cell morphology. While cortical cell numbers decreased, size increased to maintain overall shape. In contrast, xylem parenchyma cells increased approximately three fold but remained small. Normally straight flowers often curved up to 360 degrees without a significant change in size. However, the most striking phenotype was cell death in mature cells after a delay of 3-4 weeks. Trypan blue staining confirmed cell death and demonstrated that cell death was absent in similarly treated leaves of wild type TGMV-inoculated plants. Quantitative RT-PCR confirmed that the mature TGMV:RBR-inoculated leaves still maintained reduced accumulation of RBR transcript at 4 weeks compared to controls. The results suggest that either inappropriate activation of the cell cycle is lethal in plants or that RBR has other functions, unrelated to the cell cycle. The results also demonstrate that continual transcription of RBR is necessary for cell survival.}, number={1-2}, journal={PLANT MOLECULAR BIOLOGY}, author={Jordan, Chad V. and Shen, Wei and Hanley-Bowdoin, Linda K. and Robertson, Dominique}, year={2007}, month={Sep}, pages={163–175} }
 @article{shen_hanley-bowdoin_2006, title={Geminivirus infection up-regulates the expression of two Arabidopsis protein kinases related to yeast SNF1-and mammalian AMPK-activating kinases}, volume={142}, ISSN={["1532-2548"]}, DOI={10.1104/pp.106.088476}, abstractNote={Geminivirus Rep-interacting kinase 1 (GRIK1) and GRIK2 constitute a small protein kinase family in Arabidopsis (Arabidopsis thaliana). An earlier study showed that a truncated version of GRIK1 binds to the geminivirus replication protein AL1. We show here both full-length GRIK1 and GRIK2 interact with AL1 in yeast two-hybrid studies. Using specific antibodies, we showed that both Arabidopsis kinases are elevated in infected leaves. Immunoblot analysis of healthy plants revealed that GRIK1 and GRIK2 are highest in young leaf and floral tissues and low or undetectable in mature tissues. Immunohistochemical staining showed that the kinases accumulate in the shoot apical meristem, leaf primordium, and emerging petiole. Unlike the protein patterns, GRIK1 and GRIK2 transcript levels only show a small increase during infection and do not change significantly during development. Treating healthy seedlings and infected leaves with the proteasome inhibitor MG132 resulted in higher GRIK1 and GRIK2 protein levels, whereas treatment with the translation inhibitor cycloheximide reduced both kinases, demonstrating that their accumulation is modulated by posttranscriptional processes. Phylogenetic comparisons indicated that GRIK1, GRIK2, and related kinases from Medicago truncatula and rice (Oryza sativa) are most similar to the yeast kinases PAK1, TOS3, and ELM1 and the mammalian kinase CaMKK, which activate the yeast kinase SNF1 and its mammalian homolog AMPK, respectively. Complementation studies using a PAK1/TOS3/ELM1 triple mutant showed that GRIK1 and GRIK2 can functionally replace the yeast kinases, suggesting that the Arabidopsis kinases mediate one or more processes during early plant development and geminivirus infection by activating SNF1-related kinases.}, number={4}, journal={PLANT PHYSIOLOGY}, author={Shen, Wei and Hanley-Bowdoin, Linda}, year={2006}, month={Dec}, pages={1642–1655} }
 @article{shen_huber_2006, title={Polycations globally enhance binding of 14-3-3 omega to target proteins in spinach leaves}, volume={47}, ISSN={["1471-9053"]}, DOI={10.1093/pcp/pcj050}, abstractNote={The binding of 14-3-3omega to phosphorylated nitrate reductase (pNR) is stimulated by cations such as Mg(2+) or spermine, and decreased by 5'-AMP. In order to determine whether binding to other cellular proteins is affected similarly, far-Western overlays of extracts prepared from light- or dark-treated spinach (Spinacia oleracea) leaves were performed using digoxigenin (DIG)-labeled Arabidopsis 14-3-3omega. When separated by SDS-PAGE, approximately 25 proteins of >35 kDa could be resolved that interacted with DIG-labeled 14-3-3omega in the absence of added cations. The presence of 5 mM Mg(2+) or 0.5 mM spermine enhanced binding to most of the target proteins to a maximum of about a doubling of the observed binding. In most cases, the binding was dependent on phosphorylation of the target protein, whereas that was not necessarily the case for binding to target proteins that were unaffected by polycations. The extent of stimulation varied among the target proteins, but there was no indication that the nature of the cation activator (e.g. Mg(2+) vs. spermine(4+)) altered the specificity for target proteins. In addition, binding of DIG-labeled 14-3-3omega to some, but not all, target proteins was reduced by 5 mM 5'-AMP. Interestingly, light/dark treatment of spinach leaves affected the subsequent binding of DIG-labeled 14-3-3omega in the overlay assay to only a few of the target proteins, one of which was identified as NADH:nitrate reductase. Overall, the results suggest that the binding of 14-3-3s to targets in addition to pNR may also be regulated by polycations and 5'-AMP.}, number={6}, journal={PLANT AND CELL PHYSIOLOGY}, author={Shen, Wei and Huber, Steven C.}, year={2006}, month={Jun}, pages={764–771} }