TY - JOUR
T1 - Distinct roles of ezrin, radixin and moesin in maintaining the plasma membrane localizations and functions of human blood–brain barrier transporters
AU - Hoshi, Yutaro
AU - Uchida, Yasuo
AU - Kuroda, Takashi
AU - Tachikawa, Masanori
AU - Couraud, Pierre Olivier
AU - Suzuki, Takashi
AU - Terasaki, Tetsuya
N1 - Publisher Copyright:
© The Author(s) 2019.
PY - 2020/7/1
Y1 - 2020/7/1
N2 - The purpose of this study was to clarify the roles of ERM proteins (ezrin/radixin/moesin) in the regulation of membrane localization and transport activity of transporters at the human blood–brain barrier (BBB). Ezrin or moesin knockdown in a human in vitro BBB model cell line (hCMEC/D3) reduced both BCRP and GLUT1 protein expression levels on the plasma membrane. Radixin knockdown reduced not only BCRP and GLUT1, but also P-gp membrane expression. These results indicate that P-gp, BCRP and GLUT1 proteins are maintained on the plasma membrane via different ERM proteins. Furthermore, moesin knockdown caused the largest decrease of P-gp and BCRP efflux activity among the ERM proteins, whereas GLUT1 influx activity was similarly reduced by knockdown of each ERM protein. To investigate how moesin knockdown reduced P-gp efflux activity without loss of P-gp from the plasma membrane, we examined the role of PKCβI. PKCβI increased P-gp phosphorylation and reduced P-gp efflux activity. Radixin and moesin proteins were detected in isolated human brain capillaries, and their protein abundances were within a 3-fold range, compared with those in hCMEC/D3 cell line. These findings may mean that ezrin, radixin and moesin maintain the functions of different transporters in different ways at the human BBB.
AB - The purpose of this study was to clarify the roles of ERM proteins (ezrin/radixin/moesin) in the regulation of membrane localization and transport activity of transporters at the human blood–brain barrier (BBB). Ezrin or moesin knockdown in a human in vitro BBB model cell line (hCMEC/D3) reduced both BCRP and GLUT1 protein expression levels on the plasma membrane. Radixin knockdown reduced not only BCRP and GLUT1, but also P-gp membrane expression. These results indicate that P-gp, BCRP and GLUT1 proteins are maintained on the plasma membrane via different ERM proteins. Furthermore, moesin knockdown caused the largest decrease of P-gp and BCRP efflux activity among the ERM proteins, whereas GLUT1 influx activity was similarly reduced by knockdown of each ERM protein. To investigate how moesin knockdown reduced P-gp efflux activity without loss of P-gp from the plasma membrane, we examined the role of PKCβI. PKCβI increased P-gp phosphorylation and reduced P-gp efflux activity. Radixin and moesin proteins were detected in isolated human brain capillaries, and their protein abundances were within a 3-fold range, compared with those in hCMEC/D3 cell line. These findings may mean that ezrin, radixin and moesin maintain the functions of different transporters in different ways at the human BBB.
KW - Blood–brain barrier
KW - ERM proteins
KW - P-glycoprotein
KW - breast cancer resistance protein
KW - glucose transporter 1
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U2 - 10.1177/0271678X19868880
DO - 10.1177/0271678X19868880
M3 - Article
C2 - 31409174
AN - SCOPUS:85071443745
VL - 40
SP - 1533
EP - 1545
JO - Journal of Cerebral Blood Flow and Metabolism
JF - Journal of Cerebral Blood Flow and Metabolism
SN - 0271-678X
IS - 7
ER -