egg and sperm interaction

BIOCHEMICAL CHALLENGES IN THE DETECTION OF NOVEL LOW AFFINITY EXTRACELLULAR RECEPTOR INTERACTIONS

The first interaction  between egg cell and sperm of mammals takes place by binding of ZP3 and 95kDa tyrosine kinaseprotein of sperm layer. when these interaction are taken into consideration for studies , these interactions are usually found to be highly transient, in many cases often having half-lives of just fractions of a second (van der Merwe and Barclay 1994) .Beyond the difficulties in biochemically manipulating and identifying membrane proteins ,it is difficult to recognizing the extracellular intercellular binding reactions that they mediate. Primarily, this is due to their biochemical intractability: membrane-embedded proteins are difficult to solubilise in their native conformation and contain structurally-important posttranslational modifications. Also, the interaction affinities between receptor proteins are often characterised by extremely low interaction strengths (half-lives < 1 second) precluding their detection with many commonly-used high throughput methods. An assay, AVEXIS (AVidity-based EXtracellular Interaction Screen) that overcomes these technical challenges enabling the detection of very weak protein interactions (t1/2 ≤ 0.1 sec) with a low false positive rate. We can now describe this interaction of Juno and Izumo1which is vital in mammalian fertilization by using this assay (AVEXIS).