Photo of Jeff Harper, Extension

Jeff Harper

Professor

Summary

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.

Education

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

News & Journal Articles, Fact Sheets, Reports...

Book Chapter(s)
Decapitation Crosses to Test Pollen Fertility Mutations for Defects in Stigma-Style Penetration C. Wiegand, & J. Harper 2020, Methods in molecular biology (Clifton, N.J.) 2160:29-40, In Pollen and Pollen Tube Biology
Journals
A wave of specific transcript and protein accumulation accompanies pollen dehydration
These findings offer novel models and molecular candidates to further determine the mechanistic basis of dehydration and desiccation tolerance in plants.
 Sze, H., Klodová, B., Ward, J.M., Harper, J.F., Palanivelu, R., Johnson, M.A. and Honys, D. 2024, Plant Physiology, Volume 195, Issue 3, July 2024, Pages 1775–1795
Disruption of pollen tube homogalacturonan synthesis relieves pollen tube penetration defects in the Arabidopsis O-FUCOSYLTRANSFERASE1 mutant Robichaux KJ, Smith DK, Blea MN, Weigand C, Harper JF, Wallace IS. 2023, Plant Reprod. 2023 Sep;36(3):263-272
Overexpressing Vitamin C Defective 2 reduces fertility and alters Ca2+ signals in Arabidopsis pollen Weigand C, Brady D, Davis JA, Speicher T, Bacalso J, Jones D, Miller G, Choi WG, Harper JF. 2023, Plant Physiol. 2023 Apr 3;191(4):2276-2287.
Chromosomal features of the B. carinata Gomenzer genome assembly
The final piece of the Triangle of U: Evolution of the tetraploid Brassica carinata genome
Here, we report a chromosome scale 1.31-Gbp genome assembly with 156.9-fold sequencing coverage for B. carinata, completing the reference genomes comprising the classic Triangle of U, a classical theory of the evolutionary relationships among these six species.
 Won Cheol Yim, Mia L Swain, Dongna Ma, Hong An, Kevin A Bird, David D Curdie, Samuel Wang, Hyun Don Ham, Agusto Luzuriaga-Neira, Jay S Kirkwood, Manhoi Hur, Juan K Q Solomon, Jeffrey F Harper, Dylan K Kosma, David Alvarez-Ponce, John C Cushman, Patrick P Edger, Annaliese S Mason, J Chris Pires, Haibao Tang, Xingtan Zhang 2022, The Plant Cell, Volume 34, Issue 11, November 2022, Pages 4143–4172
Arabidopsis Ca2+-ATPases 1, 2, and 7 in the endoplasmic reticulum contribute to growth and pollen fitness Maryam Rahmati Ishka, Elizabeth Brown, Alexa Rosenberg, Shawn Romanowsky, James A Davis, Won-Gyu Choi, Jeffrey F Harper 2021, Plant Physiology, 2021 Jan 28;kiab021
Two lipid flippases, ALA4 and ALA5, are important for cellular expansion and vegetative growth in Arabidopsis thaliana. JA Davis, RB Pares, T Bernstein, SC McDowell, E Brown, J Stubrich, A Rosenberg, EB Cahoon, RE Cahoon, LR Poulsen, MB Palmgren, RL López-Marqués, JF Harper 2020, Plant Physiology
Direct analysis of pollen fitness by flow cytometry: implications for pollen response to stress Luria, G., N. Rutley, I. Lazar, JF. Harper and G. Miller 2019, the Plant Journal
A potential role for protein O-fucosylation during pollen-pistil interactions. Smith DK, Harper JF, Wallace IS 2018, Plant Signal & Behavior. 13(5)
Orchestrating Rapid Long-Distance Signaling in Plants with Ca2+ , ROS, and Electrical Signals. Choi, W. G., Miller, G., Wallace, I., Harper, J., Mittler, R., and Gilroy, S 2017, The Plant Journal
Identification of Phosphorylation Sites Altering Pollen Soluble Inorganic Pyrophosphatase Activity 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, Plant Physiology
Analysis and visualization of RNA-Seq expression data using RStudio, Bioconductor, and Integrated Genome Browser, Methods Loraine, A. E., Blakley, I. C., Jagadeesan, S., Harper, J., Miller, G., and Firon, N. 2015, Mol Biol 1284, 481-501.
A phospholipid uptake system in the model plant Arabidopsis thaliana. 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, Nature communications, 6, 7649.
Limonata, et al.,, Harper, J. F. (2014). ACA12 is a deregulated isoform of plasma membrane Ca2+-ATPase of Arabidopsis thaliana.

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.


 Limonta M, Romanowsky S, Olivari C, Bonza MC, Luoni L, Rosenberg A, Harper JF, De Michelis MI. 2014, Plant Mol Biol. 84:387-397.
Enhanced seed production under prolonged heat stress conditions in Arabidopsis thaliana plants deficient in cytosolic ascorbate peroxidase 2 Suzuki N, Miller G, Sejima H, Harper J, Mittler R 2013, Journal of Experimental Botany 64: 253-63
A cyclic nucleotide-gated channel (CNGC16) in pollen is critical for stress tolerance in pollen reproductive development 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, Plant Physiol. 2013 Feb;161(2):1010-20.
Na,K-ATPase is a target of cigarette smoke and reduced expression predicts poor patient outcome of smokers with lung cancer. 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, Am J Physiol Lung Cell Mol Physiol. 2012 Jun 1;302(11):
Evolution of plant p-type ATPases Pedersen CN, Axelsen KB, Harper JF, and Palmgren MG. 2012, Frontiers in Plant Science. 3:31
Disruption of the vacuolar calcium-ATPases in Arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway Curran, et al.,, Harper, J. F. 2011, Frontiers in Plant Science
The ins and outs of cellular Ca transport. Spalding, E., Harper, J. F. 2011, Current Opinion in Plant Biology
Disruption of the vacuolar calcium-ATPases in Arabidopsis results in the activation of a salicylic acid-dependent programmed cell death pathway. Borusiac, et al., Harper, J. F. 2010, Plant Physiol. 154:1158-71
Natural genetic variation in selected populations of Arabidopsis thaliana is associated with ionomic differences. 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, PLoS One. 14;5(6):e11081
Na,K-ATPase subunits as markers for epithelial-mesenchymal transition in cancer and fibrosis. 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, Mol Cancer Therapeutics 9:1515-24.
Temperature stress and plant sexual reproduction: uncovering the weakest links. Zinn, KE, M Tunc-Ozdemir, JF Harper, 2010, Journal of Experimental Botany 61: 1959-1968
Calcium-Dependent Protein Kinases Regulate Polarized Tip-Growth in Pollen Tubes. Meyers, et al.,, Harper, J. F. 2009, Plant Journal, 59, 528.
Gene expression signatures and small-molecule compounds link a protein kinase to Plasmodium falciparum motility. K., Harper, J. F., Winzeler, E. 2008, Nat Chem Bio, 4(6), 347-356.
Enhanced tolerance to oxidative stress in transgenic Arabidopsis plants expressing proteins of unknown function. Luhua, S., Ciftci-Yilmaz, S., Harper, J. F., Cushman, J. C., Mittler, R. 2008, Plant Physiology, 148(1), 280-292.
Reviews
A Fruitful Journey: Pollen Tube Navigation from Germination to Fertilization Mark A. Johnson, Jeffrey F. Harper, Ravishankar Palanivelu 2019, Annual Review of Plant Biology Volume 70