Göb Eva, Meyer-Natus Elisabeth, Benavente Ricardo, Alsheimer Manfred
Department of Cell and Developmental Biology; Biocenter; University of Würzburg; Am Hubland, Würzburg Germany.
Commun Integr Biol. 2011 Jul;4(4):440-2. doi: 10.4161/cib.15369. Epub 2011 Jul 1.
Mammalian Sun1 belongs to an evolutionarily conserved family of inner nuclear membrane proteins, which are known as SUN domain proteins. SUN domain proteins interact with KASH domain partners to form bridging complexes, so-called LINC complexes, that physically connect the nuclear interior to the cytoskeleton. LINC complexes are critical for nuclear integrity and play fundamental roles in nuclear positioning, shaping and movement. The mammalian genome codes for at least five different SUN domain proteins used for the formation of a number of different LINC complexes. Recently, we reported on the identification of several Sun1 isoforms, which tremendously enlarges the alternatives to form functional LINC complexes. We now confirmed that Sun1 actually exists in at least seven distinct splice variants. Besides that, we observed that expression of individual Sun1 isoforms remarkably depends on the cell type, suggesting a cell type-specific adaption of Sun1 dependent LINC complexes to specific cellular and physiological requirements.
哺乳动物的Sun1属于进化上保守的内核膜蛋白家族，即SUN结构域蛋白家族。SUN结构域蛋白与KASH结构域伙伴相互作用形成桥接复合物，即所谓的LINC复合物，该复合物将细胞核内部与细胞骨架物理连接起来。LINC复合物对于核完整性至关重要，并且在核定位、塑形和移动中发挥着基本作用。哺乳动物基因组编码至少五种不同的SUN结构域蛋白，用于形成多种不同的LINC复合物。最近，我们报道了几种Sun1异构体的鉴定，这极大地增加了形成功能性LINC复合物的可能性。我们现在证实，Sun1实际上至少以七种不同的剪接变体存在。除此之外，我们观察到单个Sun1异构体的表达显著依赖于细胞类型，这表明Sun1依赖的LINC复合物针对特定细胞和生理需求进行了细胞类型特异性适应。
