Prominin-1 is a heavily N-glycosylated membrane protein expressed in microvilli of epithelial cells.

Prominin-1 is differentially glycosylated in different tissues, which is suggested to cause differences in function or subcellular localisation. This is supported by previous work that has shown that glycosylation of prominin-1 is essential for its intracellular transport to the cell surface.

Previous work on uterine epithelial cells (UECs) during early pregnancy has shown that microvilli are lost at the time of implantation, concurrent with alterations in the epithelial glycocalyx.

At the time of fertilisation, prominin-1 is present in the apical portion of UECs. At the time of implantation and under the influence of progesterone, prominin-1 expression increases and redistributes, becoming concentrated at the apical plasma membrane.

Western blotting and deglycosylation analysis of isolated UECs revealed that prominin-1 is differentially glycosylated at the time of fertilisation and the time of implantation. Using ovariectomised rats, this method also showed that the glycosylation state of prominin-1 is controlled by progesterone and oestrogen.

One interesting finding of this study is that a particular glycosylated form of prominin-1 is found only at the time of fertilisation and upon treatment of ovariectomised rats with oestrogen alone. Subcellular fractionation analysis indicates that this form of prominin-1 is found only in the cytoplasm of UECs. Furthermore, this glycosylated form of prominin-1 is lost upon injection of cytochalasin-D at the time of fertilisation, suggesting it has an actin binding role.

These results are consistent with previous reports that oestrogen causes an increase in N-linked glycoprotein assembly specifically in the uterus and support the view that differential glycosylation of prominin-1 causes changes in localisation and function.