During early pregnancy, the uterine luminal epithelial cells (UECs) and endometrial stromal cells (ESCs) undergo morphological changes to enable blastocyst implantation. The present study investigates, for the first time, the cytoskeletal-associated proteins and α-actinin superfamily members, α-parvin and β-parvin, during early pregnancy in the rat uterus. These two PARVA proteins are involved in cell adhesion, morphological changes and regulation of other cytoskeletal proteins, through binding with proteins such as actin and integrin-linked kinase. α-parvin is present in UECs at fertilisation and significantly decreases by the time of implantation. β-parvin acts in opposition; significantly increasing in both UECs and ESCs at the time of implantation, suggesting a role in the process of decidualisation. Additionally, the presence of a serine-8 residue-phosphorylated α-parvin, which is associated with cell morphology changes, was found in the nuclear region of both UECs and ESCs during implantation and decidualisation. We also show that the presence of both β-parvin and phosphorylated α-parvin in ESCs is dependent on decidualisation occurring. This study demonstrates that the changing balance and localisation of the two PARVA proteins are dependent on the time of uterine receptivity, suggesting a co-dependent role in the cytoskeletal re-organisation crucial to the changing conditions necessary for implantation and decidualisation.
Keywords: Cytoskeleton; Decidualisation; Early pregnancy; Endometrium; Parvin.