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#cellular digestion

2 public questions tagged with this topic.

Cell Organelles

Which lysosomal membrane protein is required for fusion with phagosomes?

Phagosome maturation in macrophages and neutrophils converts a nascent bacteria-containing vacuole into a microbicidal phagolysosome through sequential interactions with early endosomes, late endosomes and terminal lysosomes. Acquisition of lysosomal membrane proteins marks progression, with lysosome-associated membrane proteins 1 and 2, LAMP1 and LAMP2, being the most abundant heavily glycosylated proteins delivered to maturing phagosomes, protecting membrane from hydrolases. Studies using LAMP-1 and LAMP-2 knockout mice and combined siRNA show single loss causes mild delay while double defic

Ref: Huynh et al., EMBO Journal 2007: LAMP Proteins Are Required for Fusion of Lysosomes with Phagosomes.

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Cell Organelles

The acidic pH of lysosomes is maintained by:

Lysosomes maintain a highly acidic lumen essential for optimal activity of about sixty acid hydrolases involved in macromolecular digestion and for solute transport. The steep proton gradient, pH 4.5 to 5.0 inside versus cytosolic pH 7.2, representing over two pH units and hundredfold proton concentration difference, is actively generated by vacuolar-type H+ ATPase, V-ATPase, consuming ATP. This massive multi-subunit rotary pump consists of peripheral V1 domain with A3B3 hexamer that hydrolyzes ATP and integral V0 domain forming proton channel with c-ring rotation. ATP hydrolysis drives rotati

Ref: Alberts et al., Molecular Biology of the Cell, 6th ed., Chapter 13: Lysosomes – V-ATPase and Acidification.

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