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.
Pubmed ID: 11243866 RIS Download
Amino Acid Sequence | Animals | COS Cells | Calcium-Binding Proteins | Cloning, Molecular | Dimerization | Glycoproteins | Intracellular Membranes | Membrane Glycoproteins | Membrane Proteins | Mice | Molecular Sequence Data | Nerve Tissue Proteins | Neuropeptides | Phospholipids | Phylogeny | Protein Structure, Tertiary | RNA, Messenger | Sequence Homology, Amino Acid | Synaptotagmins | Transfection