Identification of SNAREs Involved in Synaptotagmin VII-regulated Lysosomal Exocytosis

• Published in: The Journal of biological chemistry Vol. 279; no. 19; pp. 20471 - 20479
• Main Authors: Rao, Swathi K, Huynh, Chau, Proux-Gillardeaux, Veronique, Galli, Thierry, Andrews, Norma W
• Format: Journal Article
• Language: English
• Published: United States American Society for Biochemistry and Molecular Biology 07.05.2004
• Subjects: Animals; Antigens, CD - metabolism; Bacterial Proteins; beta-N-Acetylhexosaminidases - chemistry; Calcium - chemistry; Calcium - metabolism; Calcium-Binding Proteins; Carrier Proteins - metabolism; Cell Membrane - metabolism; Cell Survival; DNA - chemistry; Dose-Response Relationship, Drug; Electroporation; Exocytosis; Flow Cytometry; Lysosomal Membrane Proteins; Lysosomes - metabolism; Membrane Glycoproteins - metabolism; Membrane Glycoproteins - physiology; Membrane Proteins - metabolism; Microscopy, Fluorescence; Nerve Tissue Proteins - metabolism; Nerve Tissue Proteins - physiology; Precipitin Tests; Protein Binding; Protein Isoforms; Protein Structure, Tertiary; Qa-SNARE Proteins; Qb-SNARE Proteins; Qc-SNARE Proteins; R-SNARE Proteins; Rats; Recombinant Proteins - chemistry; SNARE Proteins; Streptolysins - pharmacology; Synaptotagmins; Vesicular Transport Proteins
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.M400798200

Ca 2+ -regulated exocytosis of lysosomes has been recognized recently as a ubiquitous process, important for the repair of plasma membrane wounds. Lysosomal exocytosis is regulated by synaptotagmin VII, a member of the synaptotagmin family of Ca 2+ -binding proteins localized on lysosomes. Here we show that Ca 2+ -dependent interaction of the synaptotagmin VII C 2 A domain with SNAP-23 is facilitated by syntaxin 4. Specific interactions also occurred in cell lysates between the plasma membrane t-SNAREs SNAP-23 and syntaxin 4 and the lysosomal v-SNARE TI-VAMP/VAMP7. Following cytosolic Ca 2+ elevation, SDS-resistant complexes containing SNAP-23, syntaxin 4, and TI-VAMP/VAMP7 were detected on membrane fractions. Lysosomal exocytosis was inhibited by the SNARE domains of syntaxin 4 and TI-VAMP/VAMP7 and by cleavage of SNAP-23 with botulinum neurotoxin E, thereby functionally implicating these SNAREs in Ca 2+ -regulated exocytosis of conventional lysosomes.