Microautophagic vacuole invagination requires calmodulin in a Ca2+-independent function.

Détails

ID Serval
serval:BIB_A7AB4F6348DC
Type
Article: article d'un périodique ou d'un magazine.
Collection
Publications
Titre
Microautophagic vacuole invagination requires calmodulin in a Ca2+-independent function.
Périodique
Journal of Biological Chemistry
Auteur(s)
Uttenweiler A., Schwarz H., Mayer A.
ISSN
0021-9258 (Print)
ISSN-L
0021-9258
Statut éditorial
Publié
Date de publication
2005
Peer-reviewed
Oui
Volume
280
Numéro
39
Pages
33289-33297
Langue
anglais
Résumé
Microautophagy is the uptake of cytosolic compounds by direct invagination of the vacuolar/lysosomal membrane. In Saccharomyces cerevisiae microautophagic uptake of soluble cytosolic proteins occurs via an autophagic tube, a highly specialized vacuolar membrane invagination. Autophagic tubes are topologically equivalent to the invaginations at multivesicular endosomes. At the tip of an autophagic tube, vesicles (autophagic bodies) pinch off into the vacuolar lumen for degradation. In this study we have identified calmodulin (Cmd1p) as necessary for microautophagy. Temperature-sensitive mutants for Cmd1p displayed reduced frequencies of vacuolar tube formation and/or abnormal tube morphologies. Microautophagic vacuole invagination was sensitive to Cmd1p antagonists as well as to antibodies to Cmd1p. cmd1 mutants with substitutions in the Ca2+-binding domains showed full invagination activity, and vacuolar membrane invagination was independent of the free Ca2+ concentration. Thus, rather than acting as a calcium-triggered switch, Cmd1p has a constitutive Ca2+-independent role in the formation of autophagic tubes. Kinetic analysis indicates that calmodulin is required for autophagic tube formation rather than for the final scission of vesicles from the tip of the tube.
Mots-clé
Amino Acid Substitution, Autophagy/drug effects, Calcium/metabolism, Calmodulin/chemistry, Calmodulin/genetics, Calmodulin/</QualifierName> <QualifierName MajorTopicYN="N">, Chelating Agents/pharmacology, Cytosol/metabolism, Egtazic Acid/analogs & derivatives, Egtazic Acid/pharmacology, Endosomes/drug effects, Endosomes/metabolism, Escherichia coli/genetics, Kinetics, Microscopy, Fluorescence, Models, Biological, Protein Structure, Tertiary, Saccharomyces cerevisiae/cytology, Saccharomyces cerevisiae/genetics, Saccharomyces cerevisiae/</QualifierName> <QualifierName MajorTopicYN="N">, Vacuoles/drug effects, Vacuoles/metabolism
Pubmed
Web of science
Open Access
Oui
Création de la notice
24/01/2008 15:06
Dernière modification de la notice
20/08/2019 15:12
Données d'usage