Ca2+-dependent Focal Exocytosis of Golgi-derived Vesicles Helps Phagocytic Uptake in Macrophages.
The role of Golgi apparatus during phagocytic uptake by macrophages has been ruled out in the past. Notably, all such reports were limited to Fcγ receptor-mediated phagocytosis. Here, we unravel a highly devolved mechanism for recruitment of Golgi-derived secretory vesicles during phagosome biogenesis, which was important for uptake of most cargos, except the IgG-coated ones. We report recruitment of mannosidase-II-positive Golgi-derived vesicles during uptake of diverse targets, including latex beads,Escherichia coli,Salmonella typhimurium, andMycobacterium tuberculosisin human and mouse macrophages. The recruitment of mannosidase-II vesicles was an early event mediated by focal exocytosis and coincided with the recruitment of transferrin receptor, VAMP3, and dynamin-2. Brefeldin A treatment inhibited mannosidase-II recruitment and phagocytic uptake of serum-coated or -uncoated latex beads andE. coliHowever, consistent with previous studies, brefeldin A treatment did not affect uptake of IgG-coated latex beads. Mechanistically, recruitment of mannosidase-II vesicles during phagocytic uptake required Ca2+from both extra- and intracellular sources apart from PI3K, microtubules, and dynamin-2. Extracellular Ca2+via voltage-gated Ca2+channels established a Ca2+-dependent local phosphatidylinositol 1,4,5-trisphosphate gradient, which guides the focal movement of Golgi-derived vesicles to the site of uptake. We confirmed Golgi-derived vesicles recruited during phagocytosis were secretory vesicles as their recruitment was sensitive to depletion of VAMP2 or NCS1, whereas recruitment of the recycling endosome marker VAMP3 was unaffected. Depletion of both VAMP2 and NCS1 individually resulted in the reduced uptake by macrophages. Together, the study provides a previously unprecedented role of Golgi-derived secretory vesicles in phagocytic uptake, the key innate defense function.
From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and.
Nimi
N
Vashi
From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and.
Syed Bilal Ahmad
SB
Andrabi
From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and.
Swapnil
S
Ghanwat
the School of Biotechnology, KIIT University, Bhubaneswar-751024, India.
Mrutyunjay
M
Suar
From the Cellular Immunology Group, International Centre for Genetic Engineering and Biotechnology, Aruna Asaf Ali Marg, New Delhi-110067 and dhiraj@icgeb.res.in.
Dhiraj
D
Kumar
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002460:Cell Line; D005089:Exocytosis / Q000502:physiology*; D006056:Golgi Apparatus / Q000502:physiology*; D006801:Humans; D007113:Immunity, Innate; D008264:Macrophages / Q000378:metabolism*; D008361:Mannosidases / Q000378:metabolism; D051379:Mice; D010587:Phagocytosis / Q000502:physiology*; D011122:Polyphosphates / Q000378:metabolism; D000067996:RAW 264.7 Cells; D022142:Secretory Vesicles / Q000378:metabolism / Q000502:physiology*
D011122:Polyphosphates; D008361:Mannosidases; C038829:mannosyl-oligosaccharide 1,3 - 1,6-alpha-mannosidase; C005692:triphosphoric acid; D002118:Calcium
Golgi; Mycobacterium tuberculosis; VAMP3; calcium; focal exocytosis; macrophage; mannosidase-II; phagocytosis; phagosome biogenesis; voltage-gated calcium channel