Medicine and Health Sciences Commons^™

The Gating Charge Should Not Be Estimated By Fitting A Two-State Model To A Q-V Curve, Francisco Bezanilla, Carlos A. Villalba-Galea

School of Pharmacy Faculty Articles

The voltage dependence of charges in voltage-sensitive proteins, typically displayed as charge versus voltage (Q-V) curves, is often quantified by fitting it to a simple two-state Boltzmann function. This procedure overlooks the fact that the fitted parameters, including the total charge, may be incorrect if the charge is moving in multiple steps. We present here the derivation of a general formulation for Q-V curves from multistate sequential models, including the case of infinite number of states. We demonstrate that the commonly used method to estimate the charge per molecule using a simple Boltzmann fit is not only inadequate, but in …

Sensing Charges Of The Ciona Intestinalis Voltage-Sensing Phosphatase, Carlos A. Villalba-Galea, Ludivine Frezza, Walter Sandtner, Francisco Bezanilla

School of Pharmacy Faculty Articles

Voltage control over enzymatic activity in voltage-sensitive phosphatases (VSPs) is conferred by a voltage-sensing domain (VSD) located in the N terminus. These VSDs are constituted by four putative transmembrane segments (S1 to S4) resembling those found in voltage-gated ion channels. The putative fourth segment (S4) of the VSD contains positive residues that likely function as voltage-sensing elements. To study in detail how these residues sense the plasma membrane potential, we have focused on five arginines in the S4 segment of the Ciona intestinalis VSP (Ci-VSP). After implementing a histidine scan, here we show that four arginine-to-histidine mutants, namely R223H to …

Ccl3 And Cxcl12 Production In Vitro By Dental Pulp Fibroblasts From Permanent And Deciduous Teeth Stimulated By Porphyromonas Gingivalis Lps, Carla Renata Sipert, Ana Carolina Morandini, Karin Cristina Da Silva Modena, Thiago José Dionísio, Maria Aparecida Andrade Moreira Machado, Sandra Helena Penha Oliveira, Ana Paula Campanelli, Carlos Ferreira Santos

All Dugoni School of Dentistry Faculty Articles

OBJECTIVE: The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS).

MATERIAL AND METHODS: Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0-10 µg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples …