title: Physicochemical analysis from real-time imaging of liposome tubulation reveals the characteristics of individual F-BAR domain proteins.
abstract: The Fer-CIP4 homology-BAR (F-BAR) domain, which was identified as a biological membrane-deforming module, has been reported to transform lipid bilayer membranes into tubules. However, details of the tubulation process, the mechanism, and the properties of the generated tubules remain unknown. Here, we successfully monitored the entire process of tubulation and the behavior of elongated tubules caused by four different F-BAR domain family proteins (FBP17, CIP4, PSTPIP1, and Pacsin2) using direct real-time imaging of giant unilamellar liposomes with dark-field optical microscopy. FBP17 and CIP4 develop many protrusions simultaneously over the entire surface of individual liposomes, whereas PSTPIP1 and Pacsin2 develop only a few protrusions from a narrow restricted part of the surface of individual liposomes. Tubules formed by FBP17 or CIP4 have higher bending rigidities than those formed by PSTPIP1 or Pacsin2. The results provide striking evidence that these four F-BAR domain family proteins should be classified into two groups: one group of FBP17 and CIP4 and another group of PSTPIP1 and Pacsin2. This classification is consistent with the phylogenetic proximity among these proteins and suggests that the nature of the respective tubulation is associated with biological function. These findings aid in the quantitative assessment with respect to manipulating the morphology of lipid bilayers using membrane-deforming proteins.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Nagoya 464-8602, Japan.
authors.forename: Yohko
authors.initials: Y
authors.lastname: Tanaka-Takiguchi
authors.forename: Toshiki
authors.initials: T
authors.lastname: Itoh
authors.forename: Kazuya
authors.initials: K
authors.lastname: Tsujita
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Yamada
authors.forename: Miho
authors.initials: M
authors.lastname: Yanagisawa
authors.forename: Kei
authors.initials: K
authors.lastname: Fujiwara
authors.forename: Akihisa
authors.initials: A
authors.lastname: Yamamoto
authors.forename: Masatoshi
authors.initials: M
authors.lastname: Ichikawa
authors.forename: Kingo
authors.initials: K
authors.lastname: Takiguchi
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry; D055598:Chemical Phenomena; D003598:Cytoskeletal Proteins / Q000737:chemistry; D050556:Fatty Acid-Binding Proteins; D008081:Liposomes / Q000737:chemistry* / Q000648:ultrastructure; D008856:Microscopy, Fluorescence; D008869:Microtubule-Associated Proteins / Q000737:chemistry* / Q000145:classification; D015778:Minor Histocompatibility Antigens; D008954:Models, Biological; D010802:Phylogeny
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; C433770:FNBP1 protein, human; D050556:Fatty Acid-Binding Proteins; D008081:Liposomes; D008869:Microtubule-Associated Proteins; D015778:Minor Histocompatibility Antigens; C120714:PACSIN2 protein, human; C486382:PSTPIP1 protein, human; C406285:TRIP10 protein, human