Apical membranes prepared by peeling from whole porcine oviducts interact with homologous sperm

Characterizations of annexin A1-interacting proteins in apical membrane and cytosolic compartments of renal tubular epithelial cells

Annexin A1 (ANXA1) is a multifunctional calcium-binding protein that can bind to membrane phospholipids. Under high-calcium condition, ANXA1 expression increases on renal epithelial cell surface, leading to enhanced adhesion of calcium oxalate (CaOx) crystal (stone material) onto the cells. To regulate various cellular processes, ANXA1 interacts with many other intracellular protein partners. However, components of the ANXA1-interacting protein complex remain unclear. Herein, we characterized the interacting complexes of apical membrane (ApANXA1) and cytosolic (cyANXA1) forms of ANXA1 in apical membrane and cytosolic compartments, respectively, of renal epithelial cells under high-calcium condition using proteomic and bioinformatic approaches. After fractionation, the ApANXA1- and CyANXA1-interacting partners were identified by immunoprecipitation followed by nanoLC‑ESI‑Qq-TOF tandem mass spectrometry (IP-MS/MS). The ANXA1-interacting partners that were common in both apical membrane and cytosolic compartments and those unique in each compartment were then analyzed for their physico-chemical properties (molecular weight, isoelectric point, amino acid contents, instability index, aliphatic index, and grand average of hydropathicity), secondary structure (α-helix, β-turn, random coil, and extended strand), molecular functions, biological processes, reactome pathways and KEGG pathways. The data demonstrated that each set of these interacting proteins exhibited common and unique characteristics and properties. The knowledge from this study may lead to better understanding of the ApANXA1 and CyAXNA1 biochemistry and functions as well as the pathophysiology of CaOx kidney stone formation induced by high-calcium condition.

Hormone-regulated PKA activity in porcine oviductal epithelial cells

The oviduct is a dynamic organ that suffers changes during the oestrous cycle and modulates gamete and embryo physiology. We analyse the possible existence of Protein kinase A (PKA)-dependent hormone-regulated pathways in porcine ampulla and primary cell cultures by 2D-electrophoresis/Western blot using anti-phospho PKA substrate antibodies. Differential phosphorylation was observed for ten proteins that were identified by mass spectrometry. The results were validated for five of the proteins: Annexin A5, Calumenin, Glyoxalase I and II and Enolase I. Immunofluorescence analyses show that Calumenin, Glyoxalase II and Enolase I change their localisation in the oviductal epithelium through the oestrus cycle. The results demonstrate the existence of PKA hormone-regulated pathways in the ampulla epithelium during the oestrus cycle.

Review: The epic journey of sperm through the female reproductive tract

Millions or billions of sperm are deposited by artificial insemination or natural mating into the cow reproductive tract but only a few arrive at the site of fertilization and only one fertilizes an oocyte. The remarkable journey that successful sperm take to reach an oocyte is long and tortuous, and includes movement through viscous fluid, avoiding dead ends and hostile immune cells. The privileged collection of sperm that complete this journey must pass selection steps in the vagina, cervix, uterus, utero-tubal junction and oviduct. In many locations in the female reproductive tract, sperm interact with the epithelium and the luminal fluid, which can affect sperm motility and function. Sperm must also be tolerated by the immune system of the female for an adequate time to allow fertilization to occur. This review emphasizes literature about cattle but also includes work in other species that emphasizes critical broad concepts. Although all parts of the female reproductive tract are reviewed, particular attention is given to the sperm destination, the oviduct.

Annexin A2 and S100A10 in the mammalian oviduct

In many mammals, upon entry into the female reproductive tract, a subpopulation of sperm is stored in the oviduct forming a functional reservoir. In the oviducts of pig and cow, Annexin A2 (AnxA2) has been linked to the binding of sperm. This protein may exist as a monomer or bound to S100A10 and both forms are associated with different biological functions. S100A10 has not yet been reported in the oviduct. The objective of this work is to analyze for the presence of S100A10 in the oviduct and to advance the study of AnxA2 and S100A10 in this organ. This work shows the presence of both proteins, AnxA2 and S100A10, in the oviduct of human, pig, cow, cat, dog and rabbit. At least in pig, AnxA2 is found devoid of S100A10 in the outer surface of the apical plasma membrane of oviductal epithelial cells, indicating that it binds to sperm as a monomer or in association with proteins different from S100A10. In the apical cytoplasm of pig oviductal epithelial cells, AnxA2 is associated with S100A10. In primary culture of porcine oviductal cells, the expression of ANXA2 is increased by progesterone, while the expression of S100A10 is increased by progesterone and estradiol. The widespread detection of both proteins in the oviduct of mammals indicates a probable conserved function in this organ. In summary, S100A10 and AnxA2 are widespread in the mammalian oviduct but AnxA2 binds sperm in vivo devoid of S100A10 and may be related to reservoir formation.