Bio

Honors & Awards


  • Research Scholarship, Clinical Fellow, California Institutes of Regenerative Medicine (10/01/2013 - 09/30/2014 (2016))
  • Extraordinary Potential in Biomedical Sciences, United States National Interest Waiver, USCIS (2011)
  • Postdoctoral Research Fellowship Award, German Research Foundation (Deutsche Forschungsgemeinschaft) (2003-2005)
  • Medical Student Research Fellowship, American Heart Association (1998)
  • Student Research Award, Biomedical Exchange Program between Europe and North America, Germany (1997-1998)

Stanford Advisors


Research & Scholarship

Lab Affiliations


Teaching

Graduate and Fellowship Programs


Publications

Journal Articles


  • Mlck1a is expressed in zebrafish thrombocytes and is an essential component of thrombus formation JOURNAL OF THROMBOSIS AND HAEMOSTASIS Tournoij, E., Weber, G. J., Akkerman, J. W., de Groot, P. G., Zon, L. I., Moll, F. L., Schulte-Merker, S. 2010; 8 (3): 588-595

    Abstract

    We have used the advantages of the zebrafish model system to demonstrate which of the vertebrate myosin light chain kinase (MLCK) genes is expressed in thrombocytes and important for thrombus formation.Here we report that Mlck1a is an essential component of thrombus formation. Phylogenetic data revealed four zebrafish orthologous for three human MLCK genes. To investigate expression of the zebrafish mlck genes in thrombocytes we compared GFP-tagged platelets with other cells by microarray analysis, and showed that mlck1a expression was 4.5-fold enriched in platelets. Furthermore, mlck1a mRNA and mRNA for the platelet-specific cd41 co-localized in thrombi. Expression of other mlck subtypes was lower in GFP-tagged platelets (mlck1b; 0.77-fold enriched) and absent in thrombi (mlck1b, -2, -3). To investigate the role of Mlck1a in thrombus formation, we knocked down mlck1a using two morpholinos. This resulted in impaired morphology changes of platelets adhering on fibrinogen. In a thrombosis model, in which thrombocytes adhere to the vessel wall damaged by laser irradiation, thrombus formation was slowed down in mlck1a-deficient embryos.We conclude that Mlck1a is the subtype of MLCK that contributes to platelet shape change and thrombus formation.

    View details for DOI 10.1111/j.1538-7836.2009.03721.x

    View details for Web of Science ID 000274453100022

    View details for PubMedID 20002541

  • Hematopoietic Stem Cell Development Is Dependent on Blood Flow CELL North, T. E., Goessling, W., Peeters, M., Li, P., Ceol, C., Lord, A. M., Weber, G. J., Harris, J., Cutting, C. C., Huang, P., Dzierzak, E., Zon, L. I. 2009; 137 (4): 736-748

    Abstract

    During vertebrate embryogenesis, hematopoietic stem cells (HSCs) arise in the aorta-gonads-mesonephros (AGM) region. We report here that blood flow is a conserved regulator of HSC formation. In zebrafish, chemical blood flow modulators regulated HSC development, and silent heart (sih) embryos, lacking a heartbeat and blood circulation, exhibited severely reduced HSCs. Flow-modifying compounds primarily affected HSC induction after the onset of heartbeat; however, nitric oxide (NO) donors regulated HSC number even when treatment occurred before the initiation of circulation, and rescued HSCs in sih mutants. Morpholino knockdown of nos1 (nnos/enos) blocked HSC development, and its requirement was shown to be cell autonomous. In the mouse, Nos3 (eNos) was expressed in HSCs in the AGM. Intrauterine Nos inhibition or embryonic Nos3 deficiency resulted in a reduction of hematopoietic clusters and transplantable murine HSCs. This work links blood flow to AGM hematopoiesis and identifies NO as a conserved downstream regulator of HSC development.

    View details for DOI 10.1016/j.cell.2009.04.023

    View details for Web of Science ID 000266114100021

    View details for PubMedID 19450519

  • montalcino, A zebrafish model for variegate porphyria EXPERIMENTAL HEMATOLOGY Dooley, K. A., Fraenkel, P. G., Langer, N. B., Schmid, B., Davidson, A. J., Weber, G., Chiang, K., Foott, H., Dwyer, C., Wingert, R. A., Zhou, Y., Paw, B. H., Zon, L. I. 2008; 36 (9): 1132-1142

    Abstract

    Inherited or acquired mutations in the heme biosynthetic pathway leads to a debilitating class of diseases collectively known as porphyrias, with symptoms that can include anemia, cutaneous photosensitivity, and neurovisceral dysfunction. In a genetic screen for hematopoietic mutants, we isolated a zebrafish mutant, montalcino (mno), which displays hypochromic anemia and porphyria. The objective of this study was to identify the defective gene and characterize the phenotype of the zebrafish mutant.Genetic linkage analysis was utilized to identify the region harboring the mno mutation. Candidate gene analysis together with reverse transcriptase polymerase chain reaction was utilized to identify the genetic mutation, which was confirmed via allele-specific oligo hybridizations. Whole mount in situ hybridizations and o-dianisidine staining were used to characterize the phenotype of the mno mutant. mRNA and morpholino microinjections were performed to phenocopy and/or rescue the mutant phenotype.Homozygous mno mutant embryos have a defect in the protoporphyrinogen oxidase (ppox) gene, which encodes the enzyme that catalyzes the oxidation of protoporphyrinogen. Homozygous mutant embryos are deficient in hemoglobin, and by 36 hours post-fertilization are visibly anemic and porphyric. The hypochromic anemia of mno embryos was partially rescued by human ppox, providing evidence for the conservation of function between human and zebrafish ppox.In humans, mutations in ppox result in variegate porphyria. At present, effective treatment for acute attacks requires the administration intravenous hemin and/or glucose. Thus, mno represents a powerful model for investigation, and a tool for future screens aimed at identifying chemical modifiers of variegate porphyria.

    View details for DOI 10.1016/j.exphem.2008.04.008

    View details for Web of Science ID 000258943100009

    View details for PubMedID 18550261

  • Duplicate VegfA genes and orthologues of the KDR receptor tyrosine kinase family mediate vascular development in the zebrafish BLOOD Bahary, N., Goishi, K., Stuckenholz, C., Weber, G., LeBlanc, J., Schafer, C. A., Berman, S. S., Klagsbrun, M., Zon, L. I. 2007; 110 (10): 3627-3636

    Abstract

    Vascular endothelial growth factor A (VEGFA) and the type III receptor tyrosine kinase receptors (RTKs) are both required for the differentiation of endothelial cells (vasculogenesis) and for the sprouting of new capillaries (angiogenesis). We have isolated a duplicated zebrafish VegfA locus, termed VegfAb, and a duplicate RTK locus with homology to KDR/FLK1 (named Kdrb). Morpholino-disrupted VegfAb embryos develop a normal circulatory system until approximately 2 to 3 days after fertilization (dpf), when defects in angiogenesis permit blood to extravasate into many tissues. Unlike the VegfAa(121) and VegfAa(165) isoforms, the VegfAb isoforms VegfAb(171) and VegfAb(210) are not normally secreted when expressed in mammalian tissue culture cells. The Kdrb locus encodes a 1361-amino acid transmembrane receptor with strong homology to mammalian KDR. Combined knockdown of both RTKs leads to defects in vascular development, suggesting that they cooperate in mediating the vascular effects of VegfA in zebrafish development. Both VegfAa and VegfAb can individually bind and promote phosphorylation of both Flk1 (Kdra) and Kdrb proteins in vitro. Taken together, our data support a model in the zebrafish, in which duplicated VegfA and multiple type III RTKs mediate vascular development.

    View details for DOI 10.1182/blood-2006-04-016378

    View details for Web of Science ID 000250946300029

    View details for PubMedID 17698971

  • Prostaglandin E2 regulates vertebrate haematopoietic stem cell homeostasis NATURE North, T. E., Goessling, W., Walkley, C. R., Lengerke, C., Kopani, K. R., Lord, A. M., Weber, G. J., Bowman, T. V., Jang, I., Grosser, T., FitzGerald, G. A., Daley, G. Q., Orkin, S. H., Zon, L. I. 2007; 447 (7147): 1007-U7

    Abstract

    Haematopoietic stem cell (HSC) homeostasis is tightly controlled by growth factors, signalling molecules and transcription factors. Definitive HSCs derived during embryogenesis in the aorta-gonad-mesonephros region subsequently colonize fetal and adult haematopoietic organs. To identify new modulators of HSC formation and homeostasis, a panel of biologically active compounds was screened for effects on stem cell induction in the zebrafish aorta-gonad-mesonephros region. Here, we show that chemicals that enhance prostaglandin (PG) E2 synthesis increased HSC numbers, and those that block prostaglandin synthesis decreased stem cell numbers. The cyclooxygenases responsible for PGE2 synthesis were required for HSC formation. A stable derivative of PGE2 improved kidney marrow recovery following irradiation injury in the adult zebrafish. In murine embryonic stem cell differentiation assays, PGE2 caused amplification of multipotent progenitors. Furthermore, ex vivo exposure to stabilized PGE2 enhanced spleen colony forming units at day 12 post transplant and increased the frequency of long-term repopulating HSCs present in murine bone marrow after limiting dilution competitive transplantation. The conserved role for PGE2 in the regulation of vertebrate HSC homeostasis indicates that modulation of the prostaglandin pathway may facilitate expansion of HSC number for therapeutic purposes.

    View details for DOI 10.1038/nature05883

    View details for Web of Science ID 000247373100048

    View details for PubMedID 17581586

  • Network of coregulated spliceosome components revealed by zebrafish mutant in recycling factor p110 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Trede, N. S., Medenbach, J., Damianov, A., Hung, L., Weber, G. J., Paw, B. H., Zhou, Y., Hersey, C., Zapata, A., Keefe, M., Barut, B. A., Stuart, A. B., Katz, T., Amemiya, C. T., Zon, L. I., Bindereif, A. 2007; 104 (16): 6608-6613

    Abstract

    The spliceosome cycle consists of assembly, catalysis, and recycling phases. Recycling of postspliceosomal U4 and U6 small nuclear ribonucleoproteins (snRNPs) requires p110/SART3, a general splicing factor. In this article, we report that the zebrafish earl grey (egy) mutation maps in the p110 gene and results in a phenotype characterized by thymus hypoplasia, other organ-specific defects, and death by 7 to 8 days postfertilization. U4/U6 snRNPs were disrupted in egy mutant embryos, demonstrating the importance of p110 for U4/U6 snRNP recycling in vivo. Surprisingly, expression profiling of the egy mutant revealed an extensive network of coordinately up-regulated components of the spliceosome cycle, providing a mechanism compensating for the recycling defect. Together, our data demonstrate that a mutation in a general splicing factor can lead to distinct defects in organ development and cause disease.

    View details for DOI 10.1073/pnas.0701919104

    View details for Web of Science ID 000245869200023

    View details for PubMedID 17416673

  • Shark rectal gland vasoactive intestinal peptide receptor: cloning, functional expression, and regulation of CFTR chloride channels AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY Bewley, M. S., Pena, J. T., Plesch, F. N., Decker, S. E., Weber, G. J., Forrest, J. N. 2006; 291 (4): R1157-R1164

    Abstract

    Vasoactive intestinal peptide (VIP) is a secretagogue that mediates chloride secretion in intestinal epithelia. We determined the relative potency of VIP and related peptides in the rectal gland of the elasmobranch dogfish shark and cloned and expressed the VIP receptor (sVIP-R) from this species. In the perfused rectal gland, VIP (5 nM) stimulated chloride secretion from 250 +/- 66 to 2,604 +/- 286 microeq x h(-1) x g(-1); the relative potency of peptide agonists was VIP > PHI = GHRH > PACAP > secretin, where PHI is peptide histidine isoleucine amide, GHRH is growth hormone-releasing hormone, and PACAP is pituitary adenylate cylase activating peptide. The cloned sVIP-R from shark rectal gland (SRG) is only 61% identical to the human VIP-R1. It maintains a long, extracellular NH2 terminus with seven cysteine residues, and has three N-glycosylation sites and eight other residues implicated in VIP binding. Two amino acids considered important for peptide binding in mammals are not present in the shark orthologue. When sVIP-R and the CFTR chloride channel were coexpressed in Xenopus oocytes, VIP increased chloride conductance from 11.3 +/- 2 to 127 +/- 34 microS. The agonist affinity for activating chloride conductance by the cloned receptor was VIP > GHRH = PHI > PACAP > secretin, a profile mirroring that in the perfused gland. The receptor differs from previously cloned VIP-Rs in having a low affinity for PACAP. Expression of both sVIP-R and CFTR mRNA was detected by quantitative PCR in shark rectal gland, intestine, and brain. These studies characterize a unique G protein-coupled receptor from the shark rectal gland that is the oldest cloned VIP-R.

    View details for DOI 10.1152/ajpregu.00078.2006

    View details for Web of Science ID 000240457600035

    View details for PubMedID 16728467

  • Gene expression analysis of zebrafish heart regeneration PLOS BIOLOGY Lien, C., Schebesta, M., Makino, S., Weber, G. J., Keating, M. T. 2006; 4 (8): 1386-1396

    Abstract

    Mammalian hearts cannot regenerate. In contrast, zebrafish hearts regenerate even when up to 20% of the ventricle is amputated. The mechanism of zebrafish heart regeneration is not understood. To systematically characterize this process at the molecular level, we generated transcriptional profiles of zebrafish cardiac regeneration by microarray analyses. Distinct gene clusters were identified based on temporal expression patterns. Genes coding for wound response/inflammatory factors, secreted molecules, and matrix metalloproteinases are expressed in regenerating heart in sequential patterns. Comparisons of gene expression profiles between heart and fin regeneration revealed a set of regeneration core molecules as well as tissue-specific factors. The expression patterns of several secreted molecules around the wound suggest that they play important roles in heart regeneration. We found that both platelet-derived growth factor-a and -b (pdgf-a and pdgf-b) are upregulated in regenerating zebrafish hearts. PDGF-B homodimers induce DNA synthesis in adult zebrafish cardiomyocytes. In addition, we demonstrate that a chemical inhibitor of PDGF receptor decreases DNA synthesis of cardiomyocytes both in vitro and in vivo during regeneration. Our data indicate that zebrafish heart regeneration is associated with sequentially upregulated wound healing genes and growth factors and suggest that PDGF signaling is required.

    View details for DOI 10.1371/journal.pbio.0040260

    View details for Web of Science ID 000240007400011

    View details for PubMedID 16869712

  • Mercury and zinc differentially inhibit shark and human CFTR orthologues: involvement of shark cysteine 102 AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY Weber, G. J., Mehr, A. P., Sirota, J. C., Aller, S. G., Decker, S. E., Dawson, D. C., Forrest, J. N. 2006; 290 (3): C793-C801

    Abstract

    The apical membrane is an important site of mercury toxicity in shark rectal gland tubular cells. We compared the effects of mercury and other thiol-reacting agents on shark CFTR (sCFTR) and human CFTR (hCFTR) chloride channels using two-electrode voltage clamping of cRNA microinjected Xenopus laevis oocytes. Chloride conductance was stimulated by perfusing with 10 microM forskolin (FOR) and 1 mM IBMX, and then thio-reactive species were added. In oocytes expressing sCFTR, FOR + IBMX mean stimulated Cl(-) conductance was inhibited 69% by 1 microM mercuric chloride and 78% by 5 microM mercuric chloride (IC(50) of 0.8 microM). Despite comparable stimulation of conductance, hCFTR was insensitive to 1 microM HgCl(2) and maximum inhibition was 15% at the highest concentration used (5 microM). Subsequent exposure to glutathione (GSH) did not reverse the inhibition of sCFTR by mercury, but dithiothreitol (DTT) completely reversed this inhibition. Zinc (50-200 microM) also reversibly inhibited sCFTR (40-75%) but did not significantly inhibit hCFTR. Similar inhibition of sCFTR but not hCFTR was observed with an organic mercurial, p-chloromercuriphenylsulfonic acid (pCMBS). The first membrane spanning domain (MSD1) of sCFTR contains two unique cysteines, C102 and C303. A chimeric construct replacing MSD1 of hCFTR with the corresponding sequence of sCFTR was highly sensitive to mercury. Site-specific mutations introducing the first but not the second shark unique cysteine in hCFTR MSD1 resulted in full sensitivity to mercury. These experiments demonstrate a profound difference in the sensitivity of shark vs. human CFTR to inhibition by three thiol-reactive substances, an effect that involves C102 in the shark orthologue.

    View details for DOI 10.1152/ajpcell.00203.2005

    View details for Web of Science ID 000235232700017

    View details for PubMedID 16236827

  • Mercury toxicity in the shark (Squalus acanthias) rectal gland: Apical CFTR chloride channels are inhibited by mercuric chloride JOURNAL OF EXPERIMENTAL ZOOLOGY PART A-ECOLOGICAL GENETICS AND PHYSIOLOGY Ratner, M. A., Decker, S. E., Aller, S. G., Weber, G., Forrest, J. N. 2006; 305A (3): 259-267

    View details for DOI 10.1002/jez.a.257

    View details for Web of Science ID 000236010700007

  • Small molecules that delay S phase suppress a zebrafish bmyb mutant NATURE CHEMICAL BIOLOGY Stern, H. M., Murphey, R. D., Shepard, J. L., Amatruda, J. F., Straub, C. T., Pfaff, K. L., Weber, G., Tallarico, J. A., King, R. W., Zon, L. I. 2005; 1 (7): 366-370

    Abstract

    Bmyb is a ubiquitously expressed transcription factor involved in cellular proliferation and cancer. Loss of bmyb function in the zebrafish mutant crash&burn (crb) results in decreased cyclin B1 expression, mitotic arrest and genome instability. These phenotypic observations in crb mutants could be attributed to the decreased expression of cyclin B1, a cell-cycle regulatory protein that is responsible for driving cell progression from G2 through mitosis. To identify small molecules that interact with the bmyb pathway, we developed an embryo-based suppressor screening strategy. In 16 weeks we screened a diverse approximately 16,000 compound library, and discovered one previously unknown compound, persynthamide (psy, 1), that suppressed bmyb-dependent mitotic defects. Psy-treated embryos showed an S-phase delay, and knockdown of the cell-cycle checkpoint regulator ataxia telangiectasia--and Rad-related kinase (ATR) abrogated the suppression of crb. The DNA synthesis inhibitors aphidicolin (2) and hydroxyurea (3) also suppressed crb. S-phase inhibition upregulated cyclin B1 mRNA, promoting the progression of cells through mitosis. Our study demonstrates that chemical suppressor screening in zebrafish can identify compounds with cell-cycle activity and can be used to identify pathways that interact with specific cell-cycle phenotypes.

    View details for DOI 10.1038/nchembio749

    View details for Web of Science ID 000233447700007

    View details for PubMedID 16372403

  • Deficiency of glutaredoxin 5 reveals Fe-S clusters are required for vertebrate haem synthesis (vol 436, pg 1035, 2005) NATURE Wingert, R. A., Galloway, J. L., Barut, B., Foott, H., Fraenkel, P., Axe, J. L., Weber, G. J., Dooley, K., DAVIDSON, A. J., Schmid, B., Paw, B. H., Shaw, G. C., Kingsley, P., Palis, J., Schubert, H., Chen, O., Kaplan, J., Zon, L. I. 2005; 437 (7060): 920-920
  • Zebrafish bmyb mutation causes genome instability and increased cancer susceptibility PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Shepard, J. L., Amatruda, J. F., Stern, H. M., Subramanian, A., FINKELSTEIN, D., Ziai, J., Finley, K. R., Pfaff, K. L., Hersey, C., Zhou, Y., Barut, B., Freedman, M., Lee, C., Spitsbergen, J., Neuberg, D., Weber, G., Golub, T. R., Glickman, J. N., Kutok, J. L., Aster, J. C., Zon, L. I. 2005; 102 (37): 13194-13199

    Abstract

    A major goal of cancer research has been to identify genes that contribute to cancer formation. The similar pathology between zebrafish and human tumors, as well as the past success of large-scale genetic screens in uncovering human disease genes, makes zebrafish an ideal system in which to find such new genes. Here, we show that a zebrafish forward genetic screen uncovered multiple cell proliferation mutants including one mutant, crash&burn (crb), that represents a loss-of-function mutation in bmyb, a transcriptional regulator and member of a putative proto-oncogene family. crb mutant embryos have defects in mitotic progression and spindle formation, and exhibit genome instability. Regulation of cyclin B levels by bmyb appears to be the mechanism of mitotic accumulation in crb. Carcinogenesis studies reveal increased cancer susceptibility in adult crb heterozygotes. Gene-expression signatures associated with loss of bmyb in zebrafish are also correlated with conserved signatures in human tumor samples, and down-regulation of the B-myb signature genes is associated with retention of p53 function. Our findings show that zebrafish screens can uncover cancer pathways, and demonstrate that loss of function of bmyb is associated with cancer.

    View details for DOI 10.1073/pnas.0506583102

    View details for Web of Science ID 000231916300035

    View details for PubMedID 16150706

  • Mutant-specific gene programs in the zebrafish BLOOD Weber, G. J., Choe, S. E., Dooley, K. A., Paffett-Lugassy, N. N., Zhou, Y., Zon, L. I. 2005; 106 (2): 521-530

    Abstract

    Hematopoiesis involves the production of stem cells, followed by the orchestrated differentiation of the blood lineages. Genetic screens in zebrafish have identified mutants with defects that disrupt specific stages of hematopoiesis and vasculogenesis, including the cloche, spadetail (tbx16), moonshine (tif1g), bloodless, and vlad tepes (gata1) mutants. To better characterize the blood program, gene expression profiling was carried out in these mutants and in scl-morphants (scl(mo)). Distinct gene clusters were demarcated by stage-specific and mutant-specific gene regulation. These were found to correlate with the transcriptional program of hematopoietic progenitor cells, as well as of the erythroid, myeloid, and vascular lineages. Among these, several novel hematopoietic and vascular genes were detected, for instance, the erythroid transcription factors znfl2 and ncoa4. A specific regulation was found for myeloid genes, as they were more strongly expressed in vlt mutants compared with other erythroid mutants. A unique gene expression pattern of up-regulated isoprenoid synthesis genes was found in cloche and scl(mo), possibly in migrating cells. In conjunction with the high conservation of vertebrate hematopoiesis, the comparison of transcriptional profiles in zebrafish blood mutants represents a versatile and powerful tool to elucidate the genetic regulation of blood and blood vessel development.

    View details for DOI 10.1182/blood-2004-11-4541

    View details for Web of Science ID 000230472100030

    View details for PubMedID 15827125

  • cGMP serves as an extracellular regulator of a Ca(2 )-dependent K( ) channel in immortalized human proximal tubule cells Cell Physiol Biochem Hirsch, J. R., Weber, G., Kleta, I., Schlatter, E. 2001; 11 (2): 77-82
  • cGMP-dependent and -independent inhibition of a K+ conductance by natriuretic peptides: Molecular and functional studies in human proximal tubule cells JOURNAL OF THE AMERICAN SOCIETY OF NEPHROLOGY Hirsch, J. R., Meyer, M., Magert, H. J., Forssmann, W. G., Mollerup, S., Herter, P., Weber, G., Cermak, R., Ankorina-Stark, I., Schlatter, E., Kruhoffer, M. 1999; 10 (3): 472-480

    Abstract

    In immortalized human kidney epithelial (IHKE-1) cells derived from proximal tubules, two natriuretic peptide receptors (NPR) were identified. In addition to NPR-A, which is bound by atrial natriuretic peptide (ANP), brain natriuretic peptide (BNP), and urodilatin (URO), a novel form of NPR-B that might be bound by C-type natriuretic peptide (CNP) was identified using PCR. This novel splice variant of NPR-B (NPR-Bi) was also found in human kidney. Whereas ANP, BNP, and URO increased intracellular cGMP levels in IHKE-1 cells in a concentration-dependent manner, CNP had no effect on cGMP levels. To determine the physiologic responses to these agonists in IHKE-1 cells, the membrane voltage (Vm) was monitored using the slow whole-cell patch-clamp technique. ANP (10 nM), BNP (10 nM), and URO (16 nM) depolarized these cells by 3 to 4 mV (n = 47, 7, and 16, respectively), an effect that could be mimicked by 0.1 mM 8-Br-cGMP (n = 15). The effects of ANP and 8-Br-cGMP were not additive (n = 4). CNP (10 nM) also depolarized these cells, by 3+/-1 mV (n = 28), despite the absence of an increase in cellular cGMP levels, indicating a cGMP-independent mechanism. In the presence of CNP, 8-Br-cGMP further depolarized Vm significantly, by 1.6+/-0.3 mV (n = 5). The depolarizations by ANP were completely abolished in the presence of Ba2+ (1 mM, n = 4) and thus can be related to inhibition of a K+ conductance in the luminal membrane of IHKE-1 cells. The depolarizations attributable to CNP were completely blocked when genistein (10 microM, n = 6), an inhibitor of tyrosine kinases, was present. These findings indicate that natriuretic peptides regulate electrogenic transport processes via cGMP-dependent and -independent pathways that influence the Vm of IHKE-1 cells.

    View details for Web of Science ID 000078807400005

    View details for PubMedID 10073597

  • A novel cGMP-regulated K+ channel in immortalized human kidney epitheliall cells (IHKE-1). J. Physiol. Hirsch, J. R., Weber, G., Kleta, I., Schlatter, E. 1999; 519 (3): 645-55

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