Endocytosis of connexin protein in adrenal cells.
The ability of adrenocorticotropin (ACTH) to affect gap junctions was examined in adrenal cells in vivo and in vitro. Treatment with ACTH increased the size and number of gap junction plaques on the cell membranes in hypophysectomized animals and in adrenal culture. Intracellular (cytoplasmic) annular gap junctions were observed in cells of the inner adrenal cortical zones and in adrenal cell cultures. To investigate the relationship of annular gap junctions to surface junctions, adrenal cells in culture were transfected with cDNA encoding a green fluorescent protein tagged connexin 43 construct (Cx43-GFP), and subsequently studied by time-lapse video microscopy, immunocytochemistry, and transmission electron microscopy (TEM). Internalization of part or all of a surface gap junction plaque resulted in annular gap junction formation. These studies support the hypothesis that cytoplasmic vesicles, initially described with TEM methods, can result from removal of gap junction plaques from the cell surface. It is suggested that hormones can play a regulatory role in cell-cell communication by influencing the availability of gap junction protein at the cell surface and that hormonally-sensitive processes might serve as a means of altering intercellular communication.
Murray
Sandra A
SA
Department of Cell Biology and Physiology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA. smurray@pitt.edu
Nickel
B M
BM
Gay
V L
VL
D000311:Adrenal Glands / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D000818:Animals; D002478:Cells, Cultured; D018031:Connexin 43 / Q000235:genetics; D017630:Connexins / Q000378:metabolism*; D004705:Endocytosis; D005260:Female; D017629:Gap Junctions / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics; D007150:Immunohistochemistry; D051379:Mice; D008810:Mice, Inbred C57BL; D008854:Microscopy, Electron; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014018:Tissue Distribution; D014162:Transfection
D018031:Connexin 43; D017630:Connexins; D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins