5ed9 | pdb_00005ed9
Crystal structure of CC1 of mouse SUN2
Structural highlights
Function[SUN2_MOUSE] Component of SUN-protein-containing multivariate complexes also called LINC complexes which link the nucleoskeleton and cytoskeleton by providing versatile outer nuclear membrane attachment sites for cytoskeletal filaments. Specifically, Syne2 and Sun2 assemble in arrays of transmembrane actin-associated nuclear (TAN) lines which are bound to F-actin cables and couple the nucleus to retrograde actin flow during actin-dependent nuclear movement. Required for interkinetic nuclear migration (INM) and essential for nucleokinesis and centrosome-nucleus coupling during radial neuronal migration in the cerebral cortex and during glial migration. Anchors chromosome movement in the prophase of meiosis and is involved in selective gene expression of coding and non-coding RNAs needed for gametogenesis. Required for telomere attachment to nuclear envelope and gametogenesis. May also function on endocytic vesicles as a receptor for Rab5-GDP and participate in the activation of Rab5.[1] [2] [3] [4] [5] Publication Abstract from PubMedSUN proteins are the core components of LINC complexes that span across the nuclear envelope for nuclear positioning and migration. SUN proteins contain at least one predicted coiled-coil domain preceding the SUN domain. Here, we found that the two coiled-coil domains (CC1 and CC2) of SUN2 exhibit distinct oligomeric states. CC2 is a monomer in solution. The structure of the CC2-SUN monomer revealed that CC2 unexpectedly folds as a three-helix bundle that interacts with the SUN domain and locks it in an inactive conformation. In contrast, CC1 is a trimer. The structure of the CC1 trimer demonstrated that CC1 is an imperfect coiled coil for the trimerization and activation of the SUN domain. Modulations of CC1 and CC2 dictate different oligomeric states of CC1-CC2-SUN, which is essential for LINC complex formation. Thus, the two coiled-coil domains of SUN2 act as the intrinsic dynamic regulators for controlling the SUN domain activity. Coiled-Coil Domains of SUN Proteins as Intrinsic Dynamic Regulators.,Nie S, Ke H, Gao F, Ren J, Wang M, Huo L, Gong W, Feng W Structure. 2016 Jan 5;24(1):80-91. doi: 10.1016/j.str.2015.10.024. Epub 2015 Dec , 10. PMID:26688217[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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