TY - JOUR
T1 - Clathrin adaptor AP2 regulates thrombin receptor constitutive internalization and endothelial cell resensitization
AU - Paing, May M.
AU - Johnston, Christopher A.
AU - Siderovski, David P.
AU - Trejo, Jo Ann
PY - 2006/4
Y1 - 2006/4
N2 - Protease-activated receptor 1 (PAR1), a G protein-coupled receptor for the coagulant protease thrombin, is irreversibly activated by proteolysis. Unactivated PAR1 cycles constitetively between the plasma membrane and intracellular stores, thereby providing a protected receptor pool that replenishes the cell surface after thrombin exposure and leads to rapid resensitization to thrombin signaling independent of de novo receptor synthesis. Here, we show that AP2, a clathrin adaptor, binds directly to a tyrosine-based motif in the cytoplasmic tail of PAR1 and is essential for constitutive receptor internalization and cellular recovery of thrombin signaling. Expression of a PAR1 tyrosine mutant or depletion of AP2 by RNA interference leads to significant inhibition of PAR1 constitutive internalization, loss of intracellular uncleaved PAR1, and failure of endothelial cells and other cell types to regain thrombin responsiveness. Our findings establish a novel role for AP2 in direct regulation of PAR1 trafficking, a process critically important to the temporal and spatial aspects of thrombin signaling.
AB - Protease-activated receptor 1 (PAR1), a G protein-coupled receptor for the coagulant protease thrombin, is irreversibly activated by proteolysis. Unactivated PAR1 cycles constitetively between the plasma membrane and intracellular stores, thereby providing a protected receptor pool that replenishes the cell surface after thrombin exposure and leads to rapid resensitization to thrombin signaling independent of de novo receptor synthesis. Here, we show that AP2, a clathrin adaptor, binds directly to a tyrosine-based motif in the cytoplasmic tail of PAR1 and is essential for constitutive receptor internalization and cellular recovery of thrombin signaling. Expression of a PAR1 tyrosine mutant or depletion of AP2 by RNA interference leads to significant inhibition of PAR1 constitutive internalization, loss of intracellular uncleaved PAR1, and failure of endothelial cells and other cell types to regain thrombin responsiveness. Our findings establish a novel role for AP2 in direct regulation of PAR1 trafficking, a process critically important to the temporal and spatial aspects of thrombin signaling.
UR - http://www.scopus.com/inward/record.url?scp=33644864081&partnerID=8YFLogxK
U2 - 10.1128/MCB.26.8.3231-3242.2006
DO - 10.1128/MCB.26.8.3231-3242.2006
M3 - Article
C2 - 16581796
AN - SCOPUS:33644864081
VL - 26
SP - 3231
EP - 3242
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
SN - 0270-7306
IS - 8
ER -