title: Electrochemical investigations of Tau protein phosphorylations and interactions with Pin1.
abstract: Phosphorylation of Tau by the protein kinase GSK-3β was monitored by electrochemical impedance spectroscopy of immobilized Tau on gold surfaces. As a result of Tau phosphorylation, the film resistance decreases significantly due to conformational changes and reorganization of the immobilized phosphorylated Tau (pTau) protein, which in turn enables the interactions of pTau with the peptidyl-prolyl cis/trans isomerase, Pin1. Interactions are specific to phospho-Ser (pSer) and phospho-Thr (pThr) residues of pTau. Impedance changes occurred as a function of pTau-Pin1 interactions and are related to the amount of Pin1 bound, which resulted in an increase of the charge-transfer resistance, R(CT). Our results clearly indicate that the isomerase Pin1 interacts favorably with pSer/pThr-Pro residues in Tau, but does not bind non-phosphorylated Tau or phospho-Tyr residues in Tau films. Our study demonstrates the utility of electrochemical impedance studies to probe protein modifications and biomolecular interactions.
authors.affiliation: Department of Physical and Environmental Sciences, University of Toronto Scarborough, 1265 Military Trail, Toronto, Canada, M1C 1A4.
authors.forename: Sanela
authors.initials: S
authors.lastname: Martić
authors.forename: Samaneh
authors.initials: S
authors.lastname: Beheshti
authors.forename: Heinz-Bernhard
authors.initials: HB
authors.lastname: Kraatz
authors.forename: David W
authors.initials: DW
authors.lastname: Litchfield
mesh_terms: D004563:Electrochemistry; D004566:Electrodes; D038362:Glycogen Synthase Kinase 3 / Q000737:chemistry / Q000378:metabolism; D000071679:Glycogen Synthase Kinase 3 beta; D006046:Gold / Q000737:chemistry; D008954:Models, Biological; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D019696:Peptidylprolyl Isomerase / Q000737:chemistry / Q000378:metabolism*; D010766:Phosphorylation; D013499:Surface Properties; D016875:tau Proteins / Q000737:chemistry* / Q000378:metabolism*
chemical_list: D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D016875:tau Proteins; D006046:Gold; D000071679:Glycogen Synthase Kinase 3 beta; D038362:Glycogen Synthase Kinase 3; D019696:Peptidylprolyl Isomerase