Synaptotagmin-like protein 1-3: a novel family of C-terminal-type tandem C2 proteins.
Synaptotagmins (Syt), rabphilin-3A, and Doc2 belong to a family of carboxyl terminal type (C-type) tandem C2 proteins and are thought to be involved in vesicular trafficking. We have cloned and characterized a novel family of C-type tandem C2 proteins, designated Slp1-3 (synaptotagmin-like protein 1-3). The Slp1-3 C2 domains show high homology to granuphilin-a C2 domains, but the amino-terminal domain of Slp1-3 does not contain any known protein motifs or a transmembrane domain. A subcellular fractionation study indicated that Slp1-3 proteins are peripheral membrane proteins. Phospholipid binding experiments indicated that Slp3 is a Ca(2+)-dependent isoform, but Slp1 and Slp2 are Ca(2+)-independent isoforms, because only the Slp3 C2A domain showed Ca(2+)-dependent phospholipid binding activity. The C-terminus of Slp1-3 also bound neurexin Ialpha in vitro, in the same manner as Syt family proteins, which may be important for the membrane association of Slp1-3. In addition, Slp family proteins are differentially distributed in different mouse tissues and at different developmental stages.
Fukuda
M
M
Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198, Japan. mnfukuda@brain.riken.go.jp
Mikoshiba
K
K
D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D002135:Calcium-Binding Proteins; D003001:Cloning, Molecular; D019281:Dimerization; D006023:Glycoproteins; D007425:Intracellular Membranes / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D009479:Neuropeptides; D010743:Phospholipids / Q000378:metabolism; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D012333:RNA, Messenger / Q000096:biosynthesis; D017386:Sequence Homology, Amino Acid; D050857:Synaptotagmins; D014162:Transfection; D033921:Vesicular Transport Proteins
D002135:Calcium-Binding Proteins; D006023:Glycoproteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D010743:Phospholipids; D012333:RNA, Messenger; C424133:Sytl1 protein, mouse; C424134:Sytl2 protein, mouse; C424135:Sytl3 protein, mouse; D033921:Vesicular Transport Proteins; C112162:neurexophilin; D050857:Synaptotagmins