TY - JOUR
T1 - Cholecystokinin-induced desensitization, receptor phosphorylation, and internalization in the CHP212 neuroblastoma cell line
AU - Rao, Rammohan V.
AU - Hadac, Elizabeth M.
AU - Roettger, Belinda F.
AU - Miller, Laurence J.
PY - 1997/6
Y1 - 1997/6
N2 - Agonist stimulation of cells often results in desensitization of the response, to protect the cell from overstimulation. We have previously shown that the type A cholecystokinin (CCK) receptor on the pancreatic acinar celt and on the model CHO-CCKR cell line undergoes desensitization in response to CCK, with receptor phosphorylation and internalization playing key roles. Although these mechanisms contribute in a cell-specific manner, no analogous information exists for the CCK receptor expressed on neuronal cells, where in vive data demonstrate a particularly sensitive response to CCK. The present study was designed to explore CCK receptor desensitization in the CHP212 neuroblastoma cell line, focusing on inositol 1,4,5-trisphosphate (IP3) responses to CCK and on recognized molecular and cellular mechanisms of desensitization. CCK promptly stimulated IP3 responses in these cells, with hormonal responsiveness rapidly and completely desensitized. Both receptor phosphorylation and internalization were observed to occur, with the former occurring most rapidly and likely being responsible for the earliest desensitization observed. Although the time course of receptor phosphorylation and dephosphorylation, and the groups of kinases involved in the neuroblastoma cell line, were most similar to those in the pancreatic cell, the movement of the agonist-bound receptor in these cells was quite different from that in the pancreatic cell and most similar to that in the CHO-CCKR cell line. This hybrid response supports the cell-specific nature of CCK receptor regulation and provides an important system to explore the molecular determinants of these processes.
AB - Agonist stimulation of cells often results in desensitization of the response, to protect the cell from overstimulation. We have previously shown that the type A cholecystokinin (CCK) receptor on the pancreatic acinar celt and on the model CHO-CCKR cell line undergoes desensitization in response to CCK, with receptor phosphorylation and internalization playing key roles. Although these mechanisms contribute in a cell-specific manner, no analogous information exists for the CCK receptor expressed on neuronal cells, where in vive data demonstrate a particularly sensitive response to CCK. The present study was designed to explore CCK receptor desensitization in the CHP212 neuroblastoma cell line, focusing on inositol 1,4,5-trisphosphate (IP3) responses to CCK and on recognized molecular and cellular mechanisms of desensitization. CCK promptly stimulated IP3 responses in these cells, with hormonal responsiveness rapidly and completely desensitized. Both receptor phosphorylation and internalization were observed to occur, with the former occurring most rapidly and likely being responsible for the earliest desensitization observed. Although the time course of receptor phosphorylation and dephosphorylation, and the groups of kinases involved in the neuroblastoma cell line, were most similar to those in the pancreatic cell, the movement of the agonist-bound receptor in these cells was quite different from that in the pancreatic cell and most similar to that in the CHO-CCKR cell line. This hybrid response supports the cell-specific nature of CCK receptor regulation and provides an important system to explore the molecular determinants of these processes.
KW - G protein-coupled receptor
KW - Receptor internalization
KW - Receptor phosphorylation
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U2 - 10.1046/j.1471-4159.1997.68062356.x
DO - 10.1046/j.1471-4159.1997.68062356.x
M3 - Article
C2 - 9166728
AN - SCOPUS:0030963954
SN - 0022-3042
VL - 68
SP - 2356
EP - 2362
JO - Journal of neurochemistry
JF - Journal of neurochemistry
IS - 6
ER -