Predictive Model of Lymphocyte-Specific Protein Tyrosine Kinase (LCK) Autoregulation

Jennifer A Rohrs,Pin Wang,Stacey D Finley

doi:10.1007/s12195-016-0438-7

Abstract

Lymphocyte-specific protein tyrosine kinase (LCK) is a key activator of T cells; however, little is known about the specific autoregulatory mechanisms that control its activity. We have constructed a model of LCK autophosphorylation and phosphorylation by the regulating kinase CSK. The model was fit to existing experimental data in the literature that presents an in vitro reconstituted membrane system, which provides more physiologically relevant kinetic measurements than traditional solution-based systems. The model is able to predict a robust mechanism of LCK autoregulation. It provides insights into the molecular causes of key site-specific phosphorylation differences between distinct experimental conditions. Probing the model also provides new hypotheses regarding the influence of individual binding and catalytic rates, which can be tested experimentally. This minimal model is required to elucidate the mechanistic interactions of LCK and CSK and can be further expanded to better understand T cell activation from a systems perspective. Our computational model enables the evaluation of LCK protein interactions that mediate T cell activation on a more quantitative level, providing new insights and testable hypotheses.Electronic supplementary materialThe online version of this article (doi:10.1007/s12195-016-0438-7) contains supplementary material, which is available to authorized users.

Highlights

Lymphocyte-specific protein tyrosine kinase (LCK) is a key regulator of T cell activation and differentiation.6,38 LCK helps to activate healthy T cells against diseased cells in the body by phosphorylating immunotyrosine activating motifs (ITAMS) on the CD3f chain of the T cell receptor (TCR).25 Mutations in the LCK gene can lead to autoimmune disease14 and contribute to cancer.7 Recently, LCK has been shown to play an important and complex role in the activation of chimeric antigen receptor (CAR) engineered T cells.22 CARs are engineered proteins that contain a variety of T cell signaling domains linked to an extracellular antibody single chain variable fragment1865-5025/16/0900-0351/0 Ó 2016 The Author(s)
In order to better understand the mechanisms through which LCK is regulated on the cell membrane, we have developed a computational model of LCK autophosphorylation and phosphorylation by the regulating kinase C-terminal Src kinase (CSK)
We have constructed a model of LCK autophosphorylation and phosphorylation by the kinase CSK

Summary

Introduction

Lymphocyte-specific protein tyrosine kinase (LCK) is a key regulator of T cell activation and differentiation. LCK helps to activate healthy T cells against diseased cells in the body by phosphorylating immunotyrosine activating motifs (ITAMS) on the CD3f chain of the T cell receptor (TCR). Mutations in the LCK gene can lead to autoimmune disease and contribute to cancer. Recently, LCK has been shown to play an important and complex role in the activation of chimeric antigen receptor (CAR) engineered T cells. CARs are engineered proteins that contain a variety of T cell signaling domains linked to an extracellular antibody single chain variable fragment1865-5025/16/0900-0351/0 Ó 2016 The Author(s). LCK has been shown to play an important and complex role in the activation of chimeric antigen receptor (CAR) engineered T cells.. CARs are engineered proteins that contain a variety of T cell signaling domains linked to an extracellular antibody single chain variable fragment. This article is published with open access at Springerlink.com (scFv). These proteins can activate T cells against a tumor-associated antigen to eradicate cancer cells.. As CARs are adapted and modified to target different types of cancer cells, understanding the detailed mechanisms that govern their activation has become more important. Despite its strong role in regulating T cell signaling, little is known about the specific mechanisms that control LCK catalytic activity

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