From the Key Laboratory of Cell Activities and Stress Adaptations of the Ministry of Education, School of Life Sciences, Lanzhou University, Lanzhou 730000, China.
the Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education and College of Life Science, Beijing Normal University, Beijing 100875, China.
J Biol Chem. 2013 Nov 8;288(45):32277-32288. doi: 10.1074/jbc.M113.483594. Epub 2013 Sep 26.
Higher order actin filament structures are necessary for cytoplasmic streaming, organelle movement, and other physiological processes. However, the mechanism by which the higher order cytoskeleton is formed in plants remains unknown. In this study, we identified a novel actin-cross-linking protein family (named CROLIN) that is well conserved only in the plant kingdom. There are six isovariants of CROLIN in the Arabidopsis genome, with CROLIN1 specifically expressed in pollen. In vitro biochemical analyses showed that CROLIN1 is a novel actin-cross-linking protein with binding and stabilizing activities. Remarkably, CROLIN1 can cross-link actin bundles into actin networks. CROLIN1 loss of function induces pollen germination and pollen tube growth hypersensitive to latrunculin B. All of these results demonstrate that CROLIN1 may play an important role in stabilizing and remodeling actin filaments by binding to and cross-linking actin filaments.
更高阶的肌动蛋白丝结构对于细胞质流、细胞器运动和其他生理过程是必要的。然而，植物中更高阶细胞骨架是如何形成的机制尚不清楚。在这项研究中，我们鉴定了一个新的肌动蛋白交联蛋白家族（命名为 CROLIN），该家族仅在植物界中被很好地保守。拟南芥基因组中有六个 CROLIN 的同工变体，CROLIN1 特异性表达于花粉中。体外生化分析表明 CROLIN1 是一种具有结合和稳定活性的新型肌动蛋白交联蛋白。值得注意的是，CROLIN1 可以将肌动蛋白束交联成肌动蛋白网络。CROLIN1 功能丧失导致花粉萌发和花粉管生长对拉普丁素 B 过度敏感。所有这些结果表明，CROLIN1 通过与肌动蛋白丝结合和交联可能在稳定和重塑肌动蛋白丝方面发挥重要作用。
