| First Author | Kato K | Year | 2016 |
| Journal | Nat Commun | Volume | 7 |
| Pages | 12198 | PubMed ID | 27416963 |
| Mgi Jnum | J:240828 | Mgi Id | MGI:5896483 |
| Doi | 10.1038/ncomms12198 | Citation | Kato K, et al. (2016) Structural and functional insights into IZUMO1 recognition by JUNO in mammalian fertilization. Nat Commun 7:12198 |
| abstractText | Sperm-egg fusion is the critical step in mammalian fertilization, and requires the interaction between IZUMO1 on the sperm surface and JUNO (also known as folate receptor (FR) 4 or IZUMO1R) on the egg surface. Whereas other FRs bind and uptake folates, JUNO binds IZUMO1 and establishes the cell-cell adhesion. However, the mechanism of IZUMO1 recognition by JUNO has remained elusive. Here we report the crystal structure of mouse JUNO, at 2.3 A resolution. A structural comparison of JUNO with the FRs revealed that JUNO and the FRs have similar overall structures, but JUNO lacks the folate-binding pocket, thereby explaining the inability of JUNO to bind folate. Further complementation of Juno knockout eggs with mutant Juno messenger RNAs revealed that the conserved, surface-exposed tryptophan residue of JUNO is required for sperm binding and fertilization. Our structure-based in vivo functional analyses provide a framework towards a mechanistic understanding of mammalian gamete recognition. |
