Jeff Harper


Photo of Jeff Harper

Professor

Department of Biochemistry and Molecular Biology
University of Nevada/Mail Stop 330
1664 North Virginia Street
Reno,  Nevada   89557

Office: (775) 784-1349
Lab: 784-1288

Fax: 784-1419

Email: jfharper@unr.edu
Building: Howard Medical Science,  Office 222

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EDUCATION

B.S. 1980, University of Illinois (Urbana)
Ph.D. 1985, Washington University (St. Louis)

ACADEMIC & RESEARCH INTEREST

The Harper lab is interested in how a plant can use as few as 28,000 genes to develop and survive under extreme environmental conditions, such as cold, heat, drought and salt stress. A primary focus is on calcium signaling. The lab employs genetic, cell, bioinformatic, and biochemical approaches, using Arabidopsis and yeast as model systems.

Specific aims are focused on questions of enzyme structure and function for members of the following three gene families.

  • Calcium Dependent Protein Kinases (CDPKs). CDPKs have a unique structure defined by the presence of a calmodulin-like regulatory domain fused to the C-terminal end of the kinase. They are only found in plants and some protist, including the human parasite Plasmodium, the causative agent of malaria.
     
  • Cyclic Nucleotide Gated Channels (CNGCs). These ion channels have been implicated in calcium signaling and are regulated by both cyclic nucleotides and calmodulin.
     
  • P-type ATPase Ion Pumps. These ion pumps are used to transport across membranes a wide variety of ions, including H+, Ca2+, Na+, and heavy metals. They are involved in ion homeostasis, nutrient acquisition from the soil, toxic ion efflux, and signal transduction.

REPRESENTATIVE PUBLICATIONS

Journals
Deborah J. Eaves, Tamanna Haque*b, Richard L. Tudorc, Yoshimi Barrond,e, Cleidiane G. Zamproniof, Nicholas P. J. Cottona, Barend H. J. de Graafg, Scott A. White, Helen J. Cooper, F. Christopher H. Franklin, Jeffery F. Harperd, and Vernonica E. Franklin-Tong 2017, Identification of Phosphorylation Sites Altering Pollen Soluble Inorganic Pyrophosphatase Activity, Plant Physiology   Read More...
Choi, W. G., Miller, G., Wallace, I., Harper, J., Mittler, R., and Gilroy, S 2017, Orchestrating Rapid Long-Distance Signaling in Plants with Ca2+ , ROS, and Electrical Signals., The Plant Journal   Read More...
Poulsen, L. R., López-Marqués, R. L., Pedas, P. R., McDowell, S. C., Brown, E., Kunze, R., Harper, J. F., Pomorski, T. G., Palmgren, M. 2015, A phospholipid uptake system in the model plant Arabidopsis thaliana., Nature communications, 6, 7649.  
Loraine, A. E., Blakley, I. C., Jagadeesan, S., Harper, J., Miller, G., and Firon, N. 2015, Analysis and visualization of RNA-Seq expression data using RStudio, Bioconductor, and Integrated Genome Browser, Methods, Mol Biol 1284, 481-501.  
Limonta M, Romanowsky S, Olivari C, Bonza MC, Luoni L, Rosenberg A, Harper JF, De Michelis MI. 2014, Limonata, et al.,, Harper, J. F. (2014). ACA12 is a deregulated isoform of plasma membrane Ca2+-ATPase of Arabidopsis thaliana., Plant Mol Biol. 84:387-397.  
Abstract:

Plant auto-inhibited Ca²?-ATPases (ACA) are crucial in defining the shape of calcium transients and therefore in eliciting plant responses to various stimuli. Arabidopsis thaliana genome encodes ten ACA isoforms that can be divided into four clusters based on gene structure and sequence homology. While isoforms from clusters 1, 2 and 4 have been characterized, virtually nothing is known about members of cluster 3 (ACA12 and ACA13). Here we show that a GFP-tagged ACA12 localizes at the plasma membrane and that expression of ACA12 rescues the phenotype of partial male sterility of a null mutant of the plasma membrane isoform ACA9, thus providing genetic evidence that ACA12 is a functional plasma membrane-resident Ca²?-ATPase. By ACA12 expression in yeast and purification by CaM-affinity chromatography, we show that, unlike other ACAs, the activity of ACA12 is not stimulated by CaM. Moreover, full length ACA12 is able to rescue a yeast mutant deficient in calcium pumps. Analysis of single point ACA12 mutants suggests that ACA12 loss of auto-inhibition can be ascribed to the lack of two acidic residues--highly conserved in other ACA isoforms--localized at the cytoplasmic edge of the second and third transmembrane segments. Together, these results support a model in which the calcium pump activity of ACA12 is primarily regulated by increasing or decreasing mRNA expression and/or protein translation and degradation.

Tunc-Ozdemir M, Tang C, Ishka MR, Brown E, Groves NR, Myers CT, Rato C, Poulsen LR, McDowell S, Miller G, Mittler R, Harper JF. 2013, A cyclic nucleotide-gated channel (CNGC16) in pollen is critical for stress tolerance in pollen reproductive development, Plant Physiol. 2013 Feb;161(2):1010-20.  
Suzuki N, Miller G, Sejima H, Harper J, Mittler R 2013, Enhanced seed production under prolonged heat stress conditions in Arabidopsis thaliana plants deficient in cytosolic ascorbate peroxidase 2, Journal of Experimental Botany 64: 253-63  
Pedersen CN, Axelsen KB, Harper JF, and Palmgren MG. 2012, Evolution of plant p-type ATPases, Frontiers in Plant Science. 3:31  
Huynh TP, Mah V, Sampson VB, Chia D, Fishbein MC, Horvath S, Alavi M, Wu DC, Harper J, Sarafian T, Dubinett SM, Langhans SA, Goodglick L, Rajasekaran AK. 2012, Na,K-ATPase is a target of cigarette smoke and reduced expression predicts poor patient outcome of smokers with lung cancer., Am J Physiol Lung Cell Mol Physiol. 2012 Jun 1;302(11):  
Curran, et al.,, Harper, J. F. 2011, Disruption of the vacuolar calcium-ATPases in Arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway, Frontiers in Plant Science  
Spalding, E., Harper, J. F. 2011, The ins and outs of cellular Ca transport., Current Opinion in Plant Biology  
Borusiac, et al., Harper, J. F. 2010, Disruption of the vacuolar calcium-ATPases in Arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway., Plant Physiol. 154:1158-71  
Rajasekaran SA, Huynh TP, Wolle DG, Espineda CE, Inge LJ, Skay A, Lassman C, Nicholas SB, Harper JF, Reeves AE, Ahmed MM, Leatherman JM, Mullin JM, Rajasekaran AK. 2010, Na,K-ATPase subunits as markers for epithelial-mesenchymal transition in cancer and fibrosis., Mol Cancer Therapeutics 9:1515-24.  
Buescher E, Achberger T, Amusan I, Giannini A, Ochsenfeld C, Rus A, Lahner B, Hoekenga O, Yakubova E, Harper JF, Guerinot ML, Zhang M, Salt DE, Baxter IR 2010, Natural genetic variation in selected populations of Arabidopsis thaliana is associated with ionomic differences., PLoS One. 14;5(6):e11081  
Zinn, KE, M Tunc-Ozdemir, JF Harper, 2010, Temperature stress and plant sexual reproduction: uncovering the weakest links., Journal of Experimental Botany 61: 1959-1968  
Meyers, et al.,, Harper, J. F. 2009, Calcium-Dependent Protein Kinases Regulate Polarized Tip-Growth in Pollen Tubes., Plant Journal, 59, 528.  
Chang, et al.,, Harper, J. F. 2009, Proteomic profiling of tandem affinity purified 14-3-3 protein complexes in Arabidopsis thaliana., Proteomics, 9, 2967.  
Luhua, S., Ciftci-Yilmaz, S., Harper, J. F., Cushman, J. C., Mittler, R. 2008, Enhanced tolerance to oxidative stress in transgenic Arabidopsis plants expressing proteins of unknown function., Plant Physiology, 148(1), 280-292.  
K., Harper, J. F., Winzeler, E. 2008, Gene expression signatures and small-molecule compounds link a protein kinase to Plasmodium falciparum motility., Nat Chem Bio, 4(6), 347-356.