title: Effects of PIP2 on membrane fusion between mast cell SNARE liposomes mediated by synaptotagmin 2.
abstract: Recent studies have revealed that SNARE proteins are involved in exocytotic release in mast cells. Previously, we reported that mast cell SNARE proteins induce membrane fusion between liposomes. Moreover, we found that synaptotagmin 2, a candidate Ca2+ sensor for mast cell exocytosis, enhanced SNARE-mediated membrane fusion via Ca2+ and phosphatidylserine. Phosphatidylinositol 4,5-bisphosphate (PIP2) is an acidic phospholipid like phosphatidylserine. In the present study, we investigated whether PIP2 is involved in the enhancement effect of synaptotagmin 2 on SNARE-mediated membrane fusion. PIP2 did not show any significant effect on SNARE-mediated membrane fusion by itself. In the presence of Ca2+, synaptotagmin 2 enhanced SNARE-mediated membrane fusion between liposomes containing PIP2. However, even in the presence of Ca2+, when we used 100% PC liposomes, synaptotagmin 2 did not show any significant effect on SNARE-mediated membrane fusion. These results indicated that PIP2 is involved in the enhancement effect of synaptotagmin 2 on membrane fusion between liposomes containing mast cell SNARE proteins.
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan.
authors.forename: Satoshi
authors.initials: S
authors.lastname: Tadokoro
authors.affiliation: School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Inoh
authors.affiliation: School of Pharmacy, Aichi Gakuin University, 1-100 Kusumoto-cho, Chikusa-ku, Nagoya 464-8650, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Nakanishi
authors.affiliation: Graduate School of Pharmaceutical Sciences, Nagoya City University, 3-1 Tanabe-dori, Mizuho-ku, Nagoya 467-8603, Japan. Electronic address: hirashim@phar.nagoya-cu.ac.jp.
authors.forename: Naohide
authors.initials: N
authors.lastname: Hirashima
mesh_terms: D008081:Liposomes / Q000737:chemistry*; D008561:Membrane Fusion; D050576:Membrane Fusion Proteins / Q000737:chemistry*; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000737:chemistry*; D050600:SNARE Proteins / Q000737:chemistry*; D050861:Synaptotagmin II / Q000737:chemistry*
chemical_list: D008081:Liposomes; D050576:Membrane Fusion Proteins; D019269:Phosphatidylinositol 4,5-Diphosphate; D050600:SNARE Proteins; D050861:Synaptotagmin II
keywords: Exocytosis; Liposome; Mast cell; Membrane fusion; SNARE; Synaptotagmin