Localization of chemoattractant receptors on Dictyostelium discoideum cells during aggregation and down-regulation.
cAMP chemoattractant receptors on the surface of Dictyostelium discoideum cells are visualized by means of immunocytochemistry. Receptor antigen is virtually absent from growing cells and begins to accumulate after about 6 hr of starvation, concomitant with the increase in surface cAMP binding activity. In aggregating cells, the antigen is uniformly distributed over the cell surface. Persistent cAMP stimulation, which leads to down-regulation of cAMP binding activity, induces a striking rearrangement of receptor antigen into patches or internal vesicles. A similar patching of receptor antigen is observed during tight aggregate formation, when surface cAMP binding activity decreases. These observations indicate that receptor down-regulation involves receptor agglomeration and suggest that receptor down-regulation takes place in vivo, when tight aggregates are being formed.
Wang
M
M
Cell Biology and Genetics Unit, University of Leiden, The Netherlands.
Van Haastert
P J
PJ
Devreotes
P N
PN
Schaap
P
P
D002449:Cell Aggregation; D002633:Chemotaxis; D000242:Cyclic AMP / Q000378:metabolism / Q000494:pharmacology; D004023:Dictyostelium / Q000378:metabolism*; D005455:Fluorescent Antibody Technique; D006651:Histocytochemistry; D011953:Receptors, Cyclic AMP / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
D011953:Receptors, Cyclic AMP; D000242:Cyclic AMP