SUN domain-containing protein 2 - Q9UH99 (SUN2_HUMAN)


Protein Feature View of PDB entries mapped to a UniProtKB sequence  

  • Number of PDB entries for Q9UH99: 5
As a component of the LINC (LInker of Nucleoskeleton and Cytoskeleton) complex, involved in the connection between the nuclear lamina and the cytoskeleton. The nucleocytoplasmic interactions established by the LINC complex play an important role in the transmission of mechanical forces across the nuclear envelope and in nuclear movement and positioning. 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. Required for nuclear migration in retinal photoreceptor progenitors implicating association with cytoplasmic dynein-dynactin and kinesin motor complexes, and probably B-type lamins; SUN1 and SUN2 seem to act redundantly. The SUN1/2:KASH5 LINC complex couples telomeres to microtubules during meiosis; SUN1 and SUN2 seem to act at least partial redundantly. 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. UniProt
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Subunit Structure
Core component of the LINC complex which is composed of inner nuclear membrane SUN domain-containing proteins coupled to outer nuclear membrane KASH domain-containing nesprins. SUN and KASH domain-containing proteins seem to bind each other promiscuously; however, differentially expression of LINC complex constituents is giving rise to specific assemblies. At least SUN1/2-containing core LINC complexes are proposed to be hexameric composed of three protomers of each KASH and SUN domain-containing protein. Interacts with SYNE2; the SUN2:SYNE2/KASH2 LINC complex is a heterohexamer; the homotrimeric cloverleave-like conformation of the SUN domain is a prerequisite for LINC complex formation in which three separate SYNE2/KASH2 peptides bind at the interface of adjacent SUN domains. Component of a probable SUN2:KASH5 LINC complex. Interacts with SYNE1 and SYNE3; probably forming respective LINC complexes. Interacts with A-type lamin. Interaction with lamins B1 and C is hardly detectable (By similarity). Interacts with EMD and RAB5A. Interacts with TMEM43 and TMEM201. UniProt
The SUN domain may play a role in the nuclear anchoring and/or migration. UniProt
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