Ohno Koji, Kato Hiroshi, Funahashi Shinji, Hasegawa Tomohiko, Sato Kohji
Department of Anatomy, Hamamatsu University School of Medicine, Handayama, Hamamatsu, Shizuoka, Japan.
J Neurochem. 2009 Nov;111(3):790-800. doi: 10.1111/j.1471-4159.2009.06370.x. Epub 2009 Sep 23.
CLP36, one of the alpha-Actinin Associated LIM Protein (ALP)/Enigma family proteins, has a wide tissue distribution, but little is known about its expression and role in the nervous system. We show here that CLP36 is expressed in sensory ganglia but not in the CNS of adult rats. In primary dorsal root ganglion (DRG) neurons, CLP36 is distributed in the soma and neurites with enrichment in the growth cones. CLP36 forms a complex with alpha-actinin and is localized to actin cytoskeleton. To examine the role of CLP36 in neuronal cells, we transfected PC12 cells with a series of CLP36 deletion mutants and found that over-expression of CLP36 PDZ domain affects neurite outgrowth. Reduction of CLP36 function in PC12 cells by RNA interference (RNAi) induced lamellipodial protrusions around cell periphery and activated growth-cone movements, resulting in an increase in the length and number of neurites. Similarly, inhibition of CLP36 in primary DRG neurons increased the rate of neurite-bearing cells. We also found that CLP36 is up-regulated in DRG neurons and facial motoneurons after nerve injury. These findings suggest that CLP36 serves as a scaffold to form a multiprotein complex that regulates actin cytoskeleton dynamics and plays a role in controlling neurite outgrowth.
CLP36是α-辅肌动蛋白相关LIM蛋白（ALP）/Enigma家族蛋白之一，具有广泛的组织分布，但对其在神经系统中的表达和作用了解甚少。我们在此表明，CLP36在成年大鼠的感觉神经节中表达，但在中枢神经系统中不表达。在初级背根神经节（DRG）神经元中，CLP36分布于胞体和神经突，在生长锥中富集。CLP36与α-辅肌动蛋白形成复合物，并定位于肌动蛋白细胞骨架。为了研究CLP36在神经元细胞中的作用，我们用一系列CLP36缺失突变体转染PC12细胞，发现CLP36 PDZ结构域的过表达影响神经突生长。通过RNA干扰（RNAi）降低PC12细胞中CLP36的功能，可诱导细胞周边的片状伪足突出并激活生长锥运动，导致神经突的长度和数量增加。同样，抑制初级DRG神经元中的CLP36可提高有神经突细胞的比例。我们还发现，神经损伤后DRG神经元和面部运动神经元中CLP36上调。这些发现表明，CLP36作为一种支架形成多蛋白复合物，调节肌动蛋白细胞骨架动力学，并在控制神经突生长中发挥作用。
