The quantification of the distribution of proteins Kir, GLT-1, and mGluR5 in murine astrocytes

Abstract

Astrocytes, a type of glial cell found within the central nervous system, are morphologically complex, and their processes are not well defined structurally or functionally. It is unknown how these processes accommodate regional demands. Small morphological and functional regions, that are highly specialized for homeostasis or synaptic signaling, may be located along the lengths of astrocyte processes. Previous research has begun to identify the distribution of proteins within astrocytes. In this study the processes, and the distribution of clusters of proteins or “puncta”, on seven previously imaged astrocytes, were analyzed using 3-D rendered surfaces generated in ImarisTM, a confocal analysis imaging software. The patterns for three proteins: mGluR5, a metabotropic glutamate receptor (n=30), GLT-1, a glutamate transporter (n=30), and Kir 4.1, an inward rectifying potassium channel (n=10) were examined along the lengths of individual processes. mGluR5 is a protein involved in synaptic signaling, and both GLT-1 and Kir 4.1 are considered more homeostatic. This study suggests that clustered regions of GLT-1 and Kir 4.1 are present within astrocytic processes, but that mGluR5 is more homogenously distributed, indicating that there may be subdomains for specialized functions within astrocytes.

* Indicates faculty mentor.