6gnx
From Proteopedia
Crystal structure of the MAJIN-TERB2 heterotetrameric complex - selenomethionine derivative
Structural highlights
FunctionMAJIN_HUMAN Meiosis-specific telomere-associated protein involved in meiotic telomere attachment to the nucleus inner membrane, a crucial step for homologous pairing and synapsis. Component of the MAJIN-TERB1-TERB2 complex, which promotes telomere cap exchange by mediating attachment of telomeric DNA to the inner nuclear membrane and replacement of the protective cap of telomeric chromosomes: in early meiosis, the MAJIN-TERB1-TERB2 complex associates with telomeric DNA and the shelterin/telosome complex. During prophase, the complex matures and promotes release of the shelterin/telosome complex from telomeric DNA. In the complex, MAJIN acts as the anchoring subunit to the nucleus inner membrane. MAJIN shows DNA-binding activity, possibly for the stabilization of telomere attachment on the nucleus inner membrane.[UniProtKB:Q9D992] Publication Abstract from PubMedMeiotic chromosomes undergo rapid prophase movements, which are thought to facilitate the formation of inter-homologue recombination intermediates that underlie synapsis, crossing over and segregation. The meiotic telomere complex (MAJIN, TERB1, TERB2) tethers telomere ends to the nuclear envelope and transmits cytoskeletal forces via the LINC complex to drive these rapid movements. Here, we report the molecular architecture of the meiotic telomere complex through the crystal structure of MAJIN-TERB2, together with light and X-ray scattering studies of wider complexes. The MAJIN-TERB2 2:2 hetero-tetramer binds strongly to DNA and is tethered through long flexible linkers to the inner nuclear membrane and two TRF1-binding 1:1 TERB2-TERB1 complexes. Our complementary structured illumination microscopy studies and biochemical findings reveal a telomere attachment mechanism in which MAJIN-TERB2-TERB1 recruits telomere-bound TRF1, which is then displaced during pachytene, allowing MAJIN-TERB2-TERB1 to bind telomeric DNA and form a mature attachment plate. Structural basis of meiotic telomere attachment to the nuclear envelope by MAJIN-TERB2-TERB1.,Dunce JM, Milburn AE, Gurusaran M, da Cruz I, Sen LT, Benavente R, Davies OR Nat Commun. 2018 Dec 17;9(1):5355. doi: 10.1038/s41467-018-07794-7. PMID:30559341[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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