Motility of spermatozoa is crucial factor for determining semen quality. Here we report Motility inhibitory factor (MIF-II) from goat epididymal plasma, revealing its structure, function, localization and motility inhibitory pathway. Structural characterization with MALDI revealed novelty of this protein while circular dichroism data confirmed its alpha helical nature. Higher dilutions of MIF-II antibody increased cauda sperm motility and induced immature/immotile caput sperm motility as tested microscopically. Higher number of sperm cells and lower dilutions of antibody induced agglutination in cauda sperm showing surface localization. Indirect immuno-fluorescence showed MIF-II localization throughout the caput sperm surface which relocated more towards acrosomal region with maturation. ELISA assay revealed gradual increase and decrease in concentration of MIF-II in epididymal plasma and plasma membrane respectively from caput to cauda. Signaling cascade that leads to sperm motility inhibition elevates nitric oxide levels through cAMP dependent pathway. MIF-II treatment doesn't alter sperm surface morphology. Expression pattern of MIF-II during epididymal maturation goes hand-in-hand with gaining motility potential as well as dormancy of spermatozoa before ejaculation. Both MIF-II and its antibody inhibit fertilization in-vitro thus expected to open new gateway for future male infertility and contraceptive development research.
International journal of biological macromolecules. 2018 Apr 30 [Epub ahead of print]
Arpita Bhoumik, Sudipta Saha, Pavan V Payghan, Prasanta Ghosh, Sandhya Rekha Dungdung
Sperm Biology Laboratory, Cell Biology and Physiology Division, CSIR-Indian Institute of Chemical Biology, Kolkata - 700032, India., Structural Biology and Bio-Informatics Division, CSIR-Indian Institute of Chemical Biology, Kolkata - 700032, India., Sperm Biology Laboratory, Cell Biology and Physiology Division, CSIR-Indian Institute of Chemical Biology, Kolkata - 700032, India. Electronic address: .