Biology Reference
In-Depth Information
Chapter 21
Role of the MTOC in T Cell Effector
Functions
Martin Poenie, Laura Christian, Sarah Tan
and Yuri Sykulev
Abstract T cells play important roles in defending the host against infections, in
allergic responses, and in the destruction of tumor cells. The directed or focused
delivery of effector molecules to another cell is minimally achieved by a two-step
process that involves focusing of secretory vesicles around the microtubule-
organizing center (MTOC) and movement of the MTOC up to the site of contact
with the target cell. This chapter is focused on mechanisms involved in the
movement of the MTOC to the target contact site in T cells. Modulated polari-
zation microscopy (MPM) and several other imaging methods were employed to
visualize the cytoskeleton in general and in particular, the dynamics of MTOC
movement. Understanding the processes of MTOC translocation has important
medical ramifications that are addressed in this chapter.
21.1 Introduction
T cells play important roles in defending the host against infections, in allergic
responses, and in destruction of tumor cells. These roles can be broadly divided into
two categories, those mediated by CD8
+
T cells, (cytotoxic T lymphocytes; CTLs)
that are aimed at killing antigenic target cells, and those mediated by CD4
+
T cells
(helper T cells) aimed at helping activate other cell types such as B cells or
M. Poenie (
&
)
L. Christian
S. Tan
Molecular Cell and Developmental Biology, University of Texas at Austin,
1 University Station Mail Code C1000, Austin, TX
78712, USA
e-mail: poenie@mail.utexas.edu
Y. Sykulev
Department of Microbiology and Immunology, Kimmel Cancer Center and Jefferson
Vaccine Center, Thomas Jefferson University, Philadelphia, PA, USA
