Sensing and clearance of apoptotic cells.

Sensing and clearance of apoptotic cells.
Curr Opin Immunol. 2020 Aug 24;68:1-8
Authors: Nagata S, Segawa K
Abstract
Macrophages specifically engulf apoptotic cells but not healthy cells. Phosphatidylserine (PtdSer) is localized at the inner leaflet of plasma membranes as a result of the action of flippases (ATP11A and 11C). When cells undergo apoptosis, caspase 3 cleaves and inactivates the flippases, while simultaneously cleaving XKR8 to activate its phospholipid scramblase activity. PtdSer is thus swiftly and irreversibly exposed to the cell surface as an 'eat me' signal. Tissue resident macrophages recognize the apoptotic cells using a PtdSer-receptor TIM4 and engulf them with TAM tyrosine-kinase receptors, and integrins. The PtdSer 'eat me' signal appears to override 'don't eat me' signals in most cases.
PMID: 32853880 [PubMed - as supplied by publisher]

Source: Current Opinion in Immunology - August 23, 2020 Category: Allergy & Immunology Authors: Nagata S, Segawa K Tags: Curr Opin Immunol Source Type: research