Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Medicine and Health Sciences
A Xenopus Oocyte Model System To Study Action Potentials, Aaron Corbin-Leftwich, Hannah E Small, Helen H Robinson, Carlos A. Villalba-Galea, Linda M Boland
A Xenopus Oocyte Model System To Study Action Potentials, Aaron Corbin-Leftwich, Hannah E Small, Helen H Robinson, Carlos A. Villalba-Galea, Linda M Boland
School of Pharmacy Faculty Articles
Action potentials (APs) are the functional units of fast electrical signaling in excitable cells. The upstroke and downstroke of an AP is generated by the competing and asynchronous action of Na+- and K+-selective voltage-gated conductances. Although a mixture of voltage-gated channels has been long recognized to contribute to the generation and temporal characteristics of the AP, understanding how each of these proteins function and are regulated during electrical signaling remains the subject of intense research. AP properties vary among different cellular types because of the expression diversity, subcellular location, and modulation of ion channels. These complexities, in addition to the …
A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver
A Human Phospholipid Phosphatase Activated By A Transmembrane Control Module, Christian R. Halaszovich, Michael G. Leitner, Angeliki Mavrantoni, Audrey Le, Ludivine Frezza, Anja Feuer, Daniela N. Schreiber, Carlos A. Villalba-Galea, Dominik Oliver
School of Pharmacy Faculty Articles
In voltage-sensitive phosphatases (VSPs), a transmembrane voltage sensor domain (VSD) controls an intracellular phosphoinositide phosphatase domain, thereby enabling immediate initiation of intracellular signals by membrane depolarization. The existence of such a mechanism in mammals has remained elusive, despite the presence of VSP-homologous proteins in mammalian cells, in particular in sperm precursor cells. Here we demonstrate activation of a human VSP (hVSP1/TPIP) by an intramolecular switch. By engineering a chimeric hVSP1 with enhanced plasma membrane targeting containing the VSD of a prototypic invertebrate VSP, we show that hVSP1 is a phosphoinositide-5-phosphatase whose predominant substrate is PI(4,5)P(2). In the chimera, enzymatic activity …
Coupling Between The Voltage-Sensing And Phosphatase Domains Of Ci-Vsp, Carlos A. Villalba-Galea, Francesco Miceli, Maurizio Taglialatela, Francisco Bezanilla
Coupling Between The Voltage-Sensing And Phosphatase Domains Of Ci-Vsp, Carlos A. Villalba-Galea, Francesco Miceli, Maurizio Taglialatela, Francisco Bezanilla
School of Pharmacy Faculty Articles
The Ciona intestinalis voltage sensor-containing phosphatase (Ci-VSP) shares high homology with the phosphatidylinositol phosphatase enzyme known as PTEN (phosphatase and tensin homologue deleted on chromosome 10). We have taken advantage of the similarity between these proteins to inquire about the coupling between the voltage sensing and the phosphatase domains in Ci-VSP. Recently, it was shown that four basic residues (R11, K13, R14, and R15) in PTEN are critical for its binding onto the membrane, required for its catalytic activity. Ci-VSP has three of the basic residues of PTEN. Here, we show that when R253 and R254 (which are the homologues …