Structural Research Of The F-BAR Domain Of Human SrGAP2

The BAR superfamily of proteins play essential roles in diverse cellularprocesses including organelle biogenesis, cell division, cell migration,secretion, and endocytosis by inducing membrane invaginations ormembrane protrusions. The BAR domain superfamily is divided into threedifferent subfamilies: the “classical” BARs/N-BARs, the F-BARs(Fes/CIP4homology-BAR), and the I-BARs (Inverse-BAR). The BAR andF-BAR subfamilies of proteins generate membrane invaginations duringprocesses such as clathrin-mediated endocytosis, whereas the I-BARsubfamily of proteins such as Missing-in-metastasis (MIM) and IRSp53produce membrane protrusions which form filopodia in vitro and in livingcells. Despite possessing an N-terminal F-BAR domain, the srGAP2protein regulates neurite outgrowth and neuronal migration by causingmembrane protrusions reminiscent of the activity of I-BAR domainproteins. In this study, the F-BAR domain of human srGAP2wasoverexpressed, purified, and crystallized. The crystals of the srGAP2 F-BAR domain protein diffracted to3.50resolution, and belonged to thespace group P21. These results will facilitate further structuraldetermination of the srGAP2F-BAR domain, and the ultimate elucidationof its peculiar behavior of inducing membrane protrusions rather thanmembrane invaginations. In this study Rab4,5,7,8,11proteins expressed bytransfect HEK293cells and F-BAR-1-357and F-BAR-1-480proteins areused in His pulldown experiment to explore the interaction between Raband F-BAR. The results suggest that F-BAR-1-357and F-BAR-1-480caninteract with Rab4,5,7,8,11.