Research
A major aspect of Barber's research is determining in molecular detail how
intracellular pH (pHi) dynamics regulate cell behaviors, with a focus on epithelial plasticity, including transformed cancer cells, and stem cell differentiation. Barber addresses questions on how
signaling networks and the
actin cytoskeleton control normal and pathological cell behavior, particularly the
post-translational modifications of proteins by
protonation and by
phosphorylation. Her research bridges
protein structure and
electrostatics with
cell biology to reveal how pHi dynamics regulate cell behaviors though protonation of titrating amino acids as a
post-translational modification to affect
protein structure and function. Her group revealed design principles and functions of "pH sensors" described as endogenous proteins regulated within the cellular pH range, which they showed have critical roles in
cell division,
migration, and
tumorigenesis. Additionally work from her group showed how increased pHi is necessary for adult and
embryonic stem cell differentiation. Through their work, Barber's research group developed new genetically-encoded
biosensors to quantitatively measure cytoplasmic and lysosome pH dynamics in clonal cells and animals. Collectively, Barber's work is highlighted by an
h-index of 46 for her group's publications and her election as a fellow for the
American Association for the Advancement of Science (AAAS), and being the plenary or keynote speaker at multiple international and national scientific conferences.
Cancer cell biology One focus of her research is on
cancer cell biology, specifically in regards to the pHi (intracellular
pH) of cancer cells., which is increased in comparison to normal cells. The research focuses on the relationship between the increased pHi and their ability to perform necessary functions. The laboratory group showed in molecular detail how it is necessary for the directed
cell migration for
metastasis. This was accomplished through the use of selective pH sensors that defined how proteins were regulated by cellular changes in pH. The group subsequently worked on the effect of increased pHi on the
glycolytic enzymes necessary for metabolic programming, somatic
mutation biology, and tumorigenic behaviors. The research uses
optogenetic tools to control the pHi of the cells,
biosensors that are genetically encoded to quantify the pHi of single cancer cells as well as cells
in vivo, and computational programming to identify ionizable residues in proteins and amino acid mutation signatures that are present in numerous cancer databases.
Stem cell differentiation The second focus of Barber's laboratory is in
stem cell differentiation, in collaboration with the laboratory of Todd Nystul. The group studies how intracellular pH and
actin filament dynamics regulate stem cell differentiation. Through their work, the group has been able to show that daughter cells have a higher pHi than naive adult and
embryonic stem cells that is necessary for their differentiation. There have been additional studies of pHi(intracellular pH), and its affect on normal cell behaviors, and Yi Liu and Diane Barber gifted two packaging plasmids for the purpose of cell science. Additionally, the laboratory studies how actin filament remodeling is necessary for the differentiation of naive embryonic stem cells. The current focus is on the transcriptional events linked to these actin dynamics. This team recently received one of five Allen Distinguished Investigator (ADI) grants of $1.32 million. == Leadership and mentoring ==
Selected publications
Research articles • Denker, SP. Huang, DC, Orlowski, J, Furthmayr, H and Barber, DL. 2000 Direct binding the Na-H exchanger NHE1 to ERM proteins regulates the cortical cytoskeleton and cell shape independently of H+ translocation. Mol Cell 6:1425-1436. (Cited in > 350 publications). PMID 11163215 • Denker, SP and Barber, DL. 2002 Cell migration requires both ion translocation and cytoskeletal anchoring by the Na-H exchanger NHE1. J Cell Biol. 159:1087-1096. (Highlighted in Journal [Using acid to find direction. J Cell Biol. 2002 159:911]) (Cited in > 340 publications) PMID 12486114 • Frantz, C, Barreiro, G, Dominguez, L, Chen, X, Eddy, R, Condeelis, J, Kelly, M, Jacobson, MP and Barber, DL. 2008 Cofilin is a pH sensor for actin free barbed end formation. J Cell Biol. 183:865-879 (Highlighted in Journal and cited in > 150 publications) PMID 19029335 • Srivastava, J, Barreiro, G, Groscurth, S, Gringas, AR, Goult, BT Critchley, DR, Kelly, MJS, Jacobson. MP and Barber, DL. 2008 Structural model and functional significance of pH-dependent talin-actin binding for focal adhesion remodeling. Proc Natl Acad Sci. 105:14436-14441. (Cited in > 90 publications) PMID 18780792 • LeClaire, LL III, Baumgartner, M, Iwasa, JH, Mullins, RD and Barber, DL. 2008 Phosphorylation of the Arp2/3 complex is necessary to nucleate actin filaments. J Cell Biol. 182:647-654. (Highlighted commentary in Journal 182:617) (Cited in > 55 publications) PMID 22125478 • Webb, BE, Chimenti, M, Jacobson, MP, Barber, D.L. 2011 Dysregulated pH: a perfect storm for cancer progression. Nature Cancer Rev. 11:671-677. (Cited in > 1200 publications) • Choi, CC, Webb, BA, Chimenti, MS, Jacobson, MP and Barber, DL. 2013 pH sensing by FAK-His58 regulates focal adhesion remodeling. J Cell Biol. 202:849-59. (Commentaries: C. Lawson and D. D. Schlaepfer, "pHocal adhesion kinase regulation is on a FERM foundation", J Cell Biol. 202:833-836 and K. Legg, "Factoring pH into FAK phosphorylation", Cell Migration Gateway) (Cited in > 70 publications). PMID 24043700 • Schönichen, A., Webb, B.E., Jacobson, M.P., and Barber, D.L. 2013 Considering protonation as a post-translational modification regulating protein structure and function. Ann Rev Biophys. 2013 42:289-314. (Cited in > 100 publications) PMID 23451893 • LeClaire, LL, Rana, MK, Baumgartner, M and Barber, DL. 2015 The Nck-interacting kinase NIK increases Arp2/3 complex activity by phosphorylating the Arp2 subunit. J Cell Biol. 208:161-170. (Highlighted commentary in Journal 208:138) PMID 25601402 • Webb BA, Forouhar F, Szu FE, Seetharaman J, Tong L, Barber DL. 2015 Structures of human phosphofructokinase-1 and atomic basis of cancer-associated mutations. Nature 523:111-114. (Cited in > 60 publications) PMID 25985179 • Ulmschneider, B., Grillo-Hill, B.K., Benitez, M., Azimova, D., Barber. D.L., Nystul, T.G. 2016 Increased intracellular pH is necessary for adult epithelial and embryonic stem cell differentiation. J. Cell Biol. 215:345-355 (featured focus article in journal) (Cited in > 60 publications) PMID 27821494 • Webb BA, Dosey AM, Wittmann T, Kollman J, Barber DL 2017 Filament assembly by the glycolytic enzyme phosphofructokinase-1. J Cell Biol 216:2305-2313. (Spotlight article in Journal “Strength in numbers: Phosphofructokinase polymerization prevails in the liver” J Cell Biol. 216:2239-2241). (Republished in a special J Cell Biol. edition on noteworthy work on cell biophysics) (cited in > 60 publications) PMID 28646105 • White KA, Grillo-Hill BK, Barber DL. 2017 Cancer cell behaviors mediated by dysregulated pH dynamics at a glance. J Cell Sci. 130(4):663-669. (Cited by > 150 publications) PMID 28202602 • White, KA, Garrido Ruiz, G, Szpiech, ZA, Strauli, NB, Hernandez, RD, Jacobson, JP and Barber, DL. 2017 Cancer-associated arginine to histidine mutations confer a gain in pH sensing to mutant proteins. Sci. Signaling 10(495). pii: eaam9931. PMID 28874603 • White, KA, Grillo-Hill, BK, Esquivel, M, Peralta, J, Bui, VN, Chire, I, Barber, DL. 2018. β-catenin is a pH sensor with decreased stability at higher intracellular pH. J Cell Biol. 217:3965-3976. Also included in JCB Special Collection of published outstanding articles on the cell biology of adhesion. PMID 30315137 • Webb BA, Aloisio FM, Charafeddine RA, Cook J, Wittmann T, and Barber DL. 2021 pHLARE: a new biosensor reveals decreased lysosome pH in cancer cells. Mol Biol Cell. 32:131-142. PMID 33237838 • Aloisio FM, Barber DL. 2022 Arp2/3 complex activity is necessary for mouse ESC differentiation, times formative pluripotency, and enables lineage specification. Stem Cell Reports. 17(6):1318-1333. PMID 35658973 == Awards and memberships ==