Characterization and subcellular localization of target membrane soluble NSF attachment protein receptors (t-SNAREs) in macrophages. Syntaxins 2, 3, and 4 are present on phagosomal membranes.

摘要: Phagosomes formed during ingestion of microorganisms by leukocytes undergo a rapid maturation, generating an acidic, microbicidal organelle. Maturation requires interactions with intracellular vesicles that dock and fuse preferentially the phagosomal membrane. The basis specificity vesiculo-phagosomal interaction has not been elucidated. By contrast, molecular vesicular fusion in other systems is better understood. At neural synapses, docking to plasma membrane are mediated protein complex including syntaxin 1. We explored whether macrophages contain syntaxins, selective phagosome results from accumulation syntaxins Isoform-specific Abs were utilized demonstrate 2, 3, 4, but 1, present murine human macrophages. Biochemical characterization demonstrated presence these on microsomes, where they integral proteins. Subcellular localization using confocal immunofluorescence microscopy 3 4 as well vesicles. Importantly, phagosomes isolated fractionation shown immunoblotting suggesting may participate maturation. density was found be comparable surface This suggests preferential result segregation this Instead, local generation second messengers vicinity trigger focal fusion.