Uteroglobin, an apically secreted protein of the uterine epithelium, is secreted non-polarized form MDCK cells and mainly basolaterally from Caco-2 cells.
A complete cDNA encoding rabbit uteroglobin was constructed and expressed in MDCK and Caco-2 cells. The MDCK cells secrete uteroglobin in approximately equal amounts to the apical and the basolateral side, whereas the Caco-2 cells secrete uteroglobin mainly to the basolateral side. Both MDCK and Caco-2 cells thus secrete uteroglobin in a non-sorted manner. It has, however, previously been shown that uteroglobin is secreted exclusively at the apical membrane in primary cell culture of endometrial epithelial cells [S.K. Mani et al. (1991) Endocrinology 128, 1563-1573]. This suggests that either the endometrial epithelium has an apical default pathway or recognises a sorting signal not recognised by MDCK cells and Caco-2 cells. Our data thus show that a soluble molecule can be secreted at the apical, the basolateral or both membranes depending on the cell type.
Department of Medical Biochemistry and Genetics, University of Copenhagen, Denmark.
L K
LK
Vogel
G
G
Suske
M
M
Beato
O
O
Norén
H
H
Sjöström
D000818:Animals; D002478:Cells, Cultured; D003001:Cloning, Molecular; D004247:DNA; D004285:Dogs; D004717:Endometrium / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D005260:Female; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D011817:Rabbits; D014598:Uteroglobin / Q000235:genetics / Q000378:metabolism*
D004247:DNA; D014598:Uteroglobin