Methods for analysis of rab27a/Munc13-4 in secretory lysosome release in hematopoietic cells.
Secretory lysosomes constitute a heterogeneous organelle of hematopoietic cells that combines the properties of regular lysosomes with those of secretory granules. Although secretory lysosomes serve essential functions, such as in the immune system and blood clotting, the mechanisms underlying the release of contents are incompletely understood. It is clear, however, that rab27a and the C2 domain protein munc13-4 serve essential functions. Mutations in these genes lead to immune disorders where the lytic granule function of cytotoxic T cells is jeopardized in humans. We identified munc13-4 as a rab27a binding protein from spleen. Munc13-4 is highly expressed in several hematopoietic cells including cytotoxic T cells and mast cells. We describe the molecular features of the interaction and requirements for localization, and show that munc13-4 is a positive regulator of secretory lysosome exocytosis.
van der Sluijs
Peter
P
Department of Cell Biology, University Medical Center Utrecht, Utrecht, The Netherlands.
Neeft
Maaike
M
van Vlijmen
Thijs
T
Elstak
Edo
E
Wieffer
Marnix
M
D000818:Animals; D003600:Cytosol / Q000378:metabolism; D006165:Guanylyl Imidodiphosphate / Q000378:metabolism; D006801:Humans; D008247:Lysosomes / Q000378:metabolism; D008565:Membrane Proteins / Q000032:analysis* / Q000276:immunology / Q000378:metabolism; D011817:Rabbits; D011994:Recombinant Proteins / Q000378:metabolism; D013154:Spleen / Q000166:cytology / Q000502:physiology; D034421:Sus scrofa; D014162:Transfection / Q000379:methods; D020691:rab GTP-Binding Proteins / Q000032:analysis*; D000075745:rab27 GTP-Binding Proteins
D008565:Membrane Proteins; D011994:Recombinant Proteins; C507969:UNC13D protein, human; D000075745:rab27 GTP-Binding Proteins; D006165:Guanylyl Imidodiphosphate; C066694:RAB27A protein, human; D020691:rab GTP-Binding Proteins