Rab3a controls exocytosis in cholecystokinin-secreting cells.
The expression of rab3A and rab3D isoforms in the enteroendocrine, cholecystokinin-secreting, cell lines STC-1 and GLUTag is here demonstrated. In contrast, rab3B is undetectable in these two cell lines, and rab3C is only slightly expressed in GLUTag cells. Using a transient co-transfection system with human growth hormone as reporter protein, we show that overexpression of the GTPase-deficient mutant rab3AQ81L, but not rab3DQ81L, significantly decreases human growth hormone secretory responses to various agonists in STC-1 cells. These results indicate that endocrine cell lines of intestinal origin express rab3A and rab3D proteins, but the GTP-bound form of rab3A only acts as a negative modulator in the control of cholecystokinin secretion from STC-1 cells.
Gevrey
J C
JC
INSERM Unité 45, Hôpital Edouard Herriot, Lyon, France.
Laurent
S
S
Saurin
J C
JC
Némoz-Gaillard
E
E
Regazzi
R
R
Chevrier
A M
AM
Chayvialle
J A
JA
Abello
J
J
D000818:Animals; D002460:Cell Line; D002766:Cholecystokinin / Q000378:metabolism*; D005089:Exocytosis / Q000502:physiology*; D017930:Genes, Reporter; D013006:Growth Hormone / Q000235:genetics; D007150:Immunohistochemistry; D051379:Mice; D009154:Mutation; D051381:Rats; D014162:Transfection; D020826:rab3A GTP-Binding Protein / Q000235:genetics / Q000502:physiology*
D013006:Growth Hormone; D002766:Cholecystokinin; D020826:rab3A GTP-Binding Protein