Cornillon Sophie, Gebbie Leigh, Benghezal Mohammed, Nair Prashant, Keller Sebastien, Wehrle-Haller Bernhard, Charette Steve J, Brückert Franz, Letourneur François, Cosson Pierre
Département de Physiologie Cellulaire et Métabolisme, Centre Médical Universitaire, 1 rue Michel Servet, 1211 Geneva 4, Switzerland.
EMBO Rep. 2006 Jun;7(6):617-21. doi: 10.1038/sj.embor.7400701. Epub 2006 May 12.
The study of free-living amoebae has proven valuable to explain the molecular mechanisms controlling phagocytosis, cell adhesion and motility. In this study, we identified a new adhesion molecule in Dictyostelium amoebae. The SibA (Similar to Integrin Beta) protein is a type I transmembrane protein, and its cytosolic, transmembrane and extracellular domains contain features also found in integrin beta chains. In addition, the conserved cytosolic domain of SibA interacts with talin, a well-characterized partner of mammalian integrins. Finally, genetic inactivation of SIBA affects adhesion to phagocytic particles, as well as cell adhesion and spreading on its substrate. It does not visibly alter the organization of the actin cytoskeleton, cellular migration or multicellular development. Our results indicate that the SibA protein is a Dictyostelium cell adhesion molecule presenting structural and functional similarities to metazoan integrin beta chains. This study sheds light on the molecular mechanisms controlling cell adhesion and their establishment during evolution.
对自由生活变形虫的研究已证明对解释控制吞噬作用、细胞黏附和运动的分子机制具有重要价值。在本研究中，我们在盘基网柄菌变形虫中鉴定出一种新的黏附分子。SibA（类似于整合素β）蛋白是一种I型跨膜蛋白，其胞质、跨膜和胞外结构域具有在整合素β链中也能找到的特征。此外，SibA保守的胞质结构域与踝蛋白相互作用，踝蛋白是哺乳动物整合素的一个特征明确的伙伴。最后，SIBA的基因失活会影响对吞噬颗粒的黏附，以及细胞在其底物上的黏附和铺展。它不会明显改变肌动蛋白细胞骨架的组织、细胞迁移或多细胞发育。我们的结果表明，SibA蛋白是一种盘基网柄菌细胞黏附分子，在结构和功能上与后生动物整合素β链相似。这项研究揭示了控制细胞黏附及其在进化过程中建立的分子机制。
