phagolysosomes

ファゴリソソーム

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2016/11/28 04:06:33」(JST)

wiki en

[Wiki en表示]

The process of phagocytosis showing phagolysosome formation.Lysosome(shown in green) fuses with phagosome to form a phagolysosome.

A phagolysosome -or endolysosome is a cytoplasmic body formed by the fusion of a phagosome with a lysosome in a process that occurs during phagocytosis.

The lysosome, containing hydrolytic enzymes digests the ingested particles in the phagosome when the phagosome migrates to the cytoplasm during phagocytosis. Membrane fusion of the phagosome and lysosome is regulated by Rab 5 protein. This G Protein allows the exchange of material between these two organelles but prevents complete fusion of their membranes. Formation of phagolysosomes are essential for the intracellular destruction of microorganisms and pathogens and requires an increase in intracellular calcium ion concentration. Reactive oxygen species and reactive nitrogen species are produced in the nutrient-limiting environment of phagolysosomes. Research studies show that phagolysosomes may contain more carbon sources and nutrients than other organelles in the endo-lysosomal pathway.

When the membranes of the phagosome and lysosome 'collide',the lysosomal contents are discharged in an explosive manner and toxic molecules are released into the phagosome.Products of the digestion are either moved into the cytoplasm (useful materials) or exported by exocytosis.

Function

Phagolysosomes function by reducing the pH of their internal environment thus making them acidic.This serves as a defense mechanism against microbes and other harmful parasites and also provides a suitable medium for degradative enzyme activity.

The Q fever causative agent,Coxiella burnetii thrives and replicates in the acidic phagolysosomes of its host cell. The acidity of the phagolysosome is essential for C.burnetii to transport glucose,glutamate,proline and also for the synthesis of nucleic acids and proteins.

Importance

Phagolysosome formation is important for the destruction of microbes and parasites.Microbes are destroyed by a combination of oxidative and non-oxidative processes in phagolysosomes.The oxidative process also known as respiratory burst includes the "non-mitochondrial" production of reactive oxygen species.

Phagolysomes inhibit fungal growth due to high cation concentration and low carbon and nitrogen sources .A typical example is the inhbition of Candida albicans filamentation.

Leishmania amastigotes obtain all their purine sources,various vitamins and a number of essential amino acids from the phagolysosome of its host.Uptake of these substances is facilitated by proton symporters.Leishmania also obtain amino acids and heme from the proteolysis of proteins in the host phagolysosome and exogenous proteins are transported to the phagolysosome by autophagy and endocytosis.

Human neutrophils also produce hypochlorous acid to destroy pathogens in phagolysosmes.

References

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

• 1. 結核の免疫学 immunology of tuberculosis
• 2. 運動以外の好中球機能 neutrophil functions other than movement
• 3. ノカルジア症の微生物学、疫学、および病因 microbiology epidemiology and pathogenesis of nocardiosis
• 4. 抗原提示細胞 antigen presenting cells
• 5. クリプトコッカス・ガッティ感染症：微生物学、疫学、および病因 cryptococcus gattii infection microbiology epidemiology and pathogenesis

English Journal

• Molecular visualizing and quantifying immune-associated peroxynitrite fluxes in phagocytes and mouse inflammation model.

• Li Z1, Yan SH2, Chen C1, Geng ZR3, Chang JY1, Chen CX1, Huang BH1, Wang ZL4.
• Biosensors & bioelectronics.Biosens Bioelectron.2017 Apr 15;90:75-82. doi: 10.1016/j.bios.2016.11.036. Epub 2016 Nov 15.
• Reactions of peroxynitrite (ONOO-) with biomolecules can lead to cytotoxic and cytoprotective events. Due to the difficulty of directly and unambiguously measuring its levels, most of the beneficial effects associated with ONOO- in vivo remain controversial or poorly characterized. Recently, optical
• PMID 27883961

• Francisella noatunensis ssp. noatunensis iglC deletion mutant protects adult zebrafish challenged with acute mortality dose of wild-type strain.

• Lampe EO1, Tandberg JI, Rishovd AL, Winther-Larsen HC.
• Diseases of aquatic organisms.Dis Aquat Organ.2017 Mar 6;123(2):123-140. doi: 10.3354/dao03087.
• The intracellular fish pathogen Francisella noatunensis remains an unsolved problem for aquaculture worldwide and an efficient vaccine is needed. In Francisella sp., IglC is an important virulence factor necessary for intracellular growth and escape from phagolysosomes. Deletion of the intracellular
• PMID 28262634

• Alternate splicing of transcripts shape macrophage response to Mycobacterium tuberculosis infection.

• Kalam H1, Fontana MF1, Kumar D1.
• PLoS pathogens.PLoS Pathog.2017 Mar 3;13(3):e1006236. doi: 10.1371/journal.ppat.1006236. [Epub ahead of print]
• Transcriptional reprogramming of macrophages upon Mycobacterium tuberculosis (Mtb) infection is widely studied; however, the significance of alternate splicing (AS) in shaping cellular responses to mycobacterial infections is not yet appreciated. Alternate splicing can influence transcript stability
• PMID 28257432

Japanese Journal

• Acquired Fanconi Syndrome with Proximal Tubular Cytoplasmic Fibrillary Inclusions of λ Light Chain Restriction

• Internal Medicine 53(2), 121-124, 2014
• NAID 130003392612

• Granulomatous Nephritis Consistent with Malakoplakia in a Cynomolgus Monkey

• Journal of Toxicologic Pathology 26(4), 419-422, 2013
• NAID 130003382460

• 脱脂米糠抽出物のヒト由来食細胞に対する免疫賦活性の検討

• 京都女子大学食物学会誌 066, 17-21, 2012-01-13
• NAID 120005541670

Related Pictures