Life Sciences Commons^™

Netrin-3 Peptide (C-19) Is A Chemorepellent And A Growth Inhibitor In Tetrahymena Thermophila, Matthew S. Merical, Kenneth W. Ward, Lois Parks, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

The netrins are a family of signaling proteins expressed throughout the animal kingdom. Netrins play important roles in developmental processes such as axonal guidance and angiogenesis. Netrin-1, for example, can act as either a chemoattractant or a chemorepellent for axonal growth cones depending upon the concentration of the protein as well as the cell type. Netrin-1 acts as a growth factor in some cell types and is expressed by some tumor cells. Netrin-3 appears to share some signaling apparatus with netrin-1, but is less widely expressed, and its physiological roles are much less understood.

Tetrahymena thermophila are free-living, eukaryotic, ciliated …

Structural Determinants Of Adhesion By Protocadherin-19 And Implications For Its Role In Epilepsy, Sharon Cooper, James D. Jontes, Marcos Sotomayor

Science and Mathematics Faculty Publications

Non-clustered δ-protocadherins are homophilic cell adhesion molecules essential for the development of the vertebrate nervous system, as several are closely linked to neurodevelopmental disorders. Mutations in protocadherin-19 (PCDH19) result in a female-limited, infant-onset form of epilepsy (PCDH19-FE). Over 100 mutations in PCDH19 have been identified in patients with PCDH19-FE, about half of which are missense mutations in the adhesive extracellular domain. Neither the mechanism of homophilic adhesion by PCDH19, nor the biochemical effects of missense mutations are understood. Here we present a crystallographic structure of the minimal adhesive fragment of the zebrafish Pcdh19 extracellular domain. This structure reveals …

Netrin-1 Peptide Is A Chemorepellent In Tetrahymena Thermophila, Heather G. Kuruvilla, Bradley Schmidt, Stephanie E. Song, Marian A. Bhajjan, Matthew S. Merical, Caleb Alley, Christopher Griffin, David Yoder, Josephine Hein, Daniel B. Kohl, Cambria R. Puffenberger, David C. Petroff, Elise Newcomer, Kortney Good, Graham Heston, Anna O. Hurtubise

Science and Mathematics Faculty Publications

Netrin-1 is a highly conserved, pleiotropic signaling molecule that can serve as a neuronal chemorepellent during vertebrate development. In vertebrates, chemorepellent signaling is mediated through the tyrosine kinase, src-1, and the tyrosine phosphatase, shp-2. Tetrahymena thermophila has been used as a model system for chemorepellent signaling because its avoidance response is easily characterized under a light microscope. Our experiments showed that netrin-1 peptide is a chemorepellent in T. thermophila at micromolar concentrations. T. thermophila adapts to netrin-1 over a time course of about 10 minutes. Netrin-adapted cells still avoid GTP, PACAP-38, and nociceptin, suggesting that netrin does not use the …

Evidence For Secretion Of A Netrin-1-Like Protein By Tetrahymena Thermophila, Victoria E. Ames, Grant Hooper, Aubrey J. Juris, Cole Knox, Jack Lightbody, Alexa C. Manthei, Jacob P. Olejarczyk, Benjamin D. Swenor, Amiah Warder, Emily B. Weindorf, Taylor L. Vander Plas, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

No abstract provided.

Acth: The Uninhibitable (Or Is It)?, Anthony Baglio, Jonathan Forsberg, Daniel Mcfarlane, Justin Nichols, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

Adrenal corticotropic hormone, or ACTH, is a peptide hormone secreted by the anterior pituitary gland. The full-length peptide is 39 amino acids long. ACTH signals through a G-protein linked receptor in humans, using the adenylyl cyclase pathway. Potassium and chloride channels have also been implicated in human ACTH signaling.

Tetrahymena thermophila are free-living, ciliated ptotozoans. These organisms exhibit avoidance behavior toward many polycationic peptides, which serve as chemorepellents. The reason for this is unknown; however, it is hypothesized that natural predators of T. thermophila secrete polycationic peptides, and that polycation avoidance allows T. thermophila to escape predation. We obtained a …

Nociceptin Is A Chemorepellent In Tetrahymena Thermophila, Nathanael Braun, Thomas Lampert, Breanne Gibson, Cheryl Nugent, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

Tetrahymena thermophila are free-living, ciliated, eukaryotic organisms that respond to stimuli by moving toward chemoattractants and avoiding chemorepellents. Chemoattractant responses involve faster ciliary beating, which propels the organisms forward more rapidly. Chemorepellent signaling involves ciliary reversal, which disrupts forward swimming, and causes the organism to jerk back and forth, swim in small circles, or spin in an attempt to get away from the repellent. Many food sources, such as proteins, are chemoattractants for Tetrahymena, while a variety of compounds are repellents. Repellents in nature are thought to come from the secretions of predators, or from ruptured organisms, which may serve …

Nociceptin Signals Through Calcium In Tetrahymena Thermophila, Tom Lampert, Tom Bertagnoli, Nathanael Braun, Jon Forsberg, Breanne Gibson, Sharon Kobinah, Cheryl Nugent, Sarah Stevens, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

Tetrahymena thermophila are free-living, ciliated, eukaryotic organisms that respond to stimuli by moving toward chemoattractants and avoiding chemorepellents. Chemoattractant responses involve faster ciliary beating, which propels the organisms forward more rapidly. Chemorepellents signaling involves ciliary reversal, which disrupts forward swimming, and causes the organisms to jerk back and forth, swim in small circles, or spin in an attempt to get away from the repellent. Many food sources, such as proteins, are chemoattractants for these organisms, while a variety of compounds are repellents. Repellents in nature are thought to come from the secretions of predators, or from ruptured organisms, which may …

Nociceptive Polycationic Peptides Are Chemorepellents In Tetrahymena Thermophila, Alicia E. Schaffner, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

Chemorepellents are compounds which cause a cell to move away from the source of the repellent, or down a concentration gradient of the compound. In ciliates such as Tetrahymena thermophila and Paramecium tetraurelia, this reorientation is accomplished by ciliary reversal, resulting in jerky or backward swimming which is known as an “avoidance reaction”. This reaction can easily be seen under a simple dissection microscope, allowing for easy characterization of ciliate behavior in different compounds.

A number of compounds are known chemorepellents in Tetrahymena thermophila, including ATP and GTP which have a negative overall charge, and polycations such as lysozyme and …

Characterizing The Polycation Receptor Of Paramecium, Eric D. Robinette, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

Unicellular eukaryotes are complex systems, performing all the tasks needed for survival within the context of a single cell. Protozoans, such as Tetrahymena and Paramecium, use chemosensory systems to detect food and to avoid predation.

Both Tetrahymena and Paramecium have been used as models for studying chemorepellents. Lysozyme, ATP, and GTP have been found to have chemorepellent activity in both ciliates. In Tetrahymena, several PACAP isoforms have been shown to bind to the same receptor as lysozyme, indicating that this receptor may be a more general “polycation receptor” (Keedy et al., 2003). The polycation receptor in Tetrahymena appears to be …

A Ciliary Sensation: Mapping Components Of The Gtp Signaling Pathway, Heather G. Kuruvilla

Science and Mathematics Faculty Presentations

GTP is a chemorepellent in Tetrahymena thermophila, causing cells to exhibit avoidance behavior, characterized by ciliary reversal. Recent work in our laboratory has shown that tyrosine kinase activity is required in order for GTP signaling to take place (Bartholomew et al., submitted for publication). Second messengers which we have found to be important for GTP signaling in Tetrahymena include nitric oxide and cGMP. Previous studies by Kim et al., 1999, have shown that a calcium-based depolarization is elicited by the application of extracellular GTP. Currently, our lab is addressing the question of where intracellular calcium is involved in the GTP …

Ets-2 And Components Of Mammalian Swi/Snf Form A Repressor Complex That Negatively Regulates The Brca1promoter, Kimberly M. Baker, Guo Wei, Alicia E. Schaffner, Michael C. Ostrowski

Science and Mathematics Faculty Publications

Ets-2 is a transcriptional activator that can be modulated by ras-dependent phosphorylation. Evidence is presented indicating that ets-2 can also act as a transcriptional repressor. In the breast cancer cell line MCF-7, exogenous ets-2 repressed the activity of a BRCA1promoter-luciferase reporter dependent on a conserved ets-2-binding site in this promoter. Conditional overproduction of ets-2 in MCF-7 cells resulted in repression of endogenousBRCA1 mRNA expression. To address the mechanism by which ets-2 could act as a repressor, a biochemical approach was used to identify proteins that interacted with the ets-2 pointed domain. From this analysis, components of the …

Ets-2 Is A Target For An Akt (Protein Kinase B)/Jun N-Terminal Kinase Signaling Pathway In Macrophages Of Motheaten-Viable Mutant Mice, Alicia E. Schaffner, James L. Smith, Joseph K. Hofmeister, Matthew Hartman, Guo Wei, David Forsthoefel, David A. Hume, Michael C. Ostrowski

Science and Mathematics Faculty Publications

The transcription factor ets-2 was phosphorylated at residue threonine 72 in a colony-stimulating factor 1 (CSF-1)- and mitogen-activated protein kinase-independent manner in macrophages isolated from motheaten-viable (me-v) mice. The CSF-1 and ets-2 target genes coding for Bcl-x, urokinase plasminogen activator, and scavenger receptor were also expressed at high levels independent of CSF-1 addition to me-v cells. Akt (protein kinase B) was constitutively active in me-v macrophages, and an Akt immunoprecipitate catalyzed phosphorylation of ets-2 at threonine 72. The p54 isoform of c-jun N-terminal kinase–stress-activated kinase (JNK- SAPK) coimmunoprecipitated with Akt from me-v macrophages, and treatment ofme-v cells …