caa a22 4500 39755639X CHVBK 20180308164803.0 cr unu---uuuuu 161202e199609 xx s 000 0 eng 10.1093/oxfordjournals.jbchem.a021464 doi (NATIONALLICENCE)oxford-10.1093/oxfordjournals.jbchem.a021464 Calcium-Dependent Phospholipid Binding to the C2A Domain of a Ubiquitous Form of Double C2 Protein (Doc2β) [Elektronische Daten] [Toshio Kojima, Mitsunori Fukuda, Jun Aruga, Katsuhiko Mikoshiba] Rabphilin 3A and Doc2α are synaptic vesicle-associated proteins, and are thought to function as Ca2+ sensors in neurotransmitter release. If either rabphilin 3A or Doc2α plays a role in membrane trafficking, like the synaptotagmins, then non-neural forms should be present. Here we describe the isolation of a mouse cDNA which encodes a novel Doc2 homologue (Doc2β) that is present in all tissues. The encoded protein, which is highly homologous to human Doc2α (70% identity), is composed of 412 amino acids with a calculated relative molecular mass (Mr) of 45,837. The sequence identity is especially high in two C2 domains (74% in C2A and 84% in C2B). Northern and Western blot analyses have shown that Doc2£ is expressed in all cell lines and tissues tested. Ca2+-dependent phospholipid binding assaying of recombinant fusion proteins revealed that the single C2A domain, but not the C2B domain, of Doc2β binds phosphatidycholine and phosphatidylserine (2.5 : 1, w/w) liposomes. The binding is Ca2+-dependent, with an EC50 value of approximately 1 μM and a Hill coefficient of approximately 3, which are comparable to those of synaptotagmins, rabphilin 3A and Doc2α. Our results suggest that Doc2β is involved in constitutive membrane trafficking. © 1996 BY THE JOURNAL OF BIOCHEMISTRY Regular Papers nationallicence C2 domain nationallicence Ca2+ sensor nationallicence Doc2 nationallicence rabphilin 3A nationallicence synaptotagmin nationallicence Kojima Toshio Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut Fukuda Mitsunori Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut Aruga Jun Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut Mikoshiba Katsuhiko Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut The Journal of Biochemistry Oxford University Press 120/3(1996-09), 671-676 0021-924X 120:3<671 1996 120 jbchem https://doi.org/10.1093/oxfordjournals.jbchem.a021464 text/html Onlinezugriff via DOI 1 other jats NATIONALLICENCE 856 40 https://doi.org/10.1093/oxfordjournals.jbchem.a021464 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Kojima Toshio Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut NATIONALLICENCE 700 1- Fukuda Mitsunori Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut NATIONALLICENCE 700 1- Aruga Jun Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut NATIONALLICENCE 700 1- Mikoshiba Katsuhiko Molecular Neurobiology Laboratory, Tsukuba Life Science Center, The Institute of Physical and Chemical Research (RIKEN) 3-1-1 Koyadai, Tsukuba, Ibaraki 305 aut NATIONALLICENCE 773 0- The Journal of Biochemistry Oxford University Press 120/3(1996-09), 671-676 0021-924X 120:3<671 1996 120 jbchem Metadata rights reserved CC BY-NC-4.0 http://creativecommons.org/licenses/by-nc/4.0 nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-oxford