Premium
Expression and phosphorylation status of β‐arrestin‐1 in normal, reactive, and neoplastic human brain
Author(s) -
Bourne T David,
Papin Jason A,
Locke Corinne N,
Glass George F,
Mandell James W
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.706.15
Subject(s) - biology , microbiology and biotechnology , phosphorylation , immunohistochemistry , immunology
β‐arrestins act as signal terminators and scaffold proteins for G protein‐coupled receptor‐mediated signal transduction. This study characterizes the distribution, cellular localization, and phosphorylation state of β‐arrestin‐1 (BAR1) in normal, reactive, and neoplastic human brain tissue. Fixed brain tissues from temporal lobectomy, autopsy, and glioblastoma (GBM) specimens were analyzed by immunohistochemistry using rabbit Mabs directed against BAR1 and phospho (Ser412)‐BAR1. BAR1 and p‐BAR1 immunoreactivity was identified in several neuronal cell populations and in oligodendroglia, pineocytes, ependymal cells, and subependymal glia. Areas of reactive gliosis showed both BAR1 and p‐BAR1 expression, while a majority of GBM specimens showed only BAR1 expression. BAR1 expression was prominent in most neuronal populations, showing predominantly cytoplasmic with occasional nuclear localization. Although undetectable in quiescent astrocytes, reactive astroglia exhibited BAR1 expression and phosphorylation. In contrast, although BAR1 is consistently expressed in most glioblastomas, it appears to be maintained in a dephosphorylated state by unknown mechanisms. Since dephosphorylated BAR1 is responsible for engaging Src and ERK/MAP kinase activation, this may have implications for aberrant signaling in GBM. Supported by Coulter Foundation Translational Research Grant (JWM and JAP).