Identification of SNAREs involved in synaptotagmin VII-regulated lysosomal exocytosis.
Ca2+-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 Ca2+-binding proteins localized on lysosomes. Here we show that Ca2+-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 Ca2+ 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 Ca2+-regulated exocytosis of conventional lysosomes.
Section of Microbial Pathogenesis and Department of Cell Biology, Yale University School of Medicine, Boyer Center for Molecular Medicine, 295 Congress Avenue, New Haven, CT 06511, USA.
Swathi K
SK
Rao
Chau
C
Huynh
Veronique
V
Proux-Gillardeaux
Thierry
T
Galli
Norma W
NW
Andrews
D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001426:Bacterial Proteins; D002118:Calcium / Q000737:chemistry / Q000378:metabolism; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002470:Cell Survival; D004247:DNA / Q000737:chemistry; D004305:Dose-Response Relationship, Drug; D018274:Electroporation; D005089:Exocytosis; D005434:Flow Cytometry; D051907:Lysosomal Membrane Proteins; D008247:Lysosomes / Q000378:metabolism*; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000502:physiology*; D008565:Membrane Proteins / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009419:Nerve Tissue Proteins / Q000378:metabolism / Q000502:physiology*; D011233:Precipitin Tests; D011485:Protein Binding; D020033:Protein Isoforms; D017434:Protein Structure, Tertiary; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; D051381:Rats; D011994:Recombinant Proteins / Q000737:chemistry; D050600:SNARE Proteins; D013301:Streptolysins / Q000494:pharmacology; D050857:Synaptotagmins; D033921:Vesicular Transport Proteins; D001619:beta-N-Acetylhexosaminidases / Q000737:chemistry
D015703:Antigens, CD; D001426:Bacterial Proteins; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D051907:Lysosomal Membrane Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D020033:Protein Isoforms; D050765:Qa-SNARE Proteins; D050766:Qb-SNARE Proteins; D050767:Qc-SNARE Proteins; D050683:R-SNARE Proteins; D011994:Recombinant Proteins; C100493:SNAP23 protein, human; D050600:SNARE Proteins; D013301:Streptolysins; C494304:Syt7 protein, rat; C496926:Vamp7 protein, rat; D033921:Vesicular Transport Proteins; C025964:streptolysin O; D050857:Synaptotagmins; D004247:DNA; D001619:beta-N-Acetylhexosaminidases; D002118:Calcium