4dxt | pdb_00004dxt
Human SUN2 (AA 522-717)
Structural highlights
FunctionSUN2_HUMAN 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] Publication Abstract from PubMedLinker of nucleoskeleton and cytoskeleton (LINC) complexes span the nuclear envelope and are composed of KASH and SUN proteins residing in the outer and inner nuclear membrane, respectively. LINC formation relies on direct binding of KASH and SUN in the perinuclear space. Thereby, molecular tethers are formed that can transmit forces for chromosome movements, nuclear migration, and anchorage. We present crystal structures of the human SUN2-KASH1/2 complex, the core of the LINC complex. The SUN2 domain is rigidly attached to a trimeric coiled coil that prepositions it to bind three KASH peptides. The peptides bind in three deep and expansive grooves formed between adjacent SUN domains, effectively acting as molecular glue. In addition, a disulfide between conserved cysteines on SUN and KASH covalently links both proteins. The structure provides the basis of LINC complex formation and suggests a model for how LINC complexes might arrange into higher-order clusters to enhance force-coupling. LINC Complexes Form by Binding of Three KASH Peptides to Domain Interfaces of Trimeric SUN Proteins.,Sosa BA, Rothballer A, Kutay U, Schwartz TU Cell. 2012 May 25;149(5):1035-47. PMID:22632968[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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