Degradation of GFP-labelled POM121, a non-invasive sensor of nuclear apoptosis, precedes clustering of nuclear pores and externalisation of phosphatidylserine

• The nuclear pore membrane protein POM121 is specifically degraded during apoptosis by a caspase-3-dependent process enabling early detection of apoptosis in living cells expressing POM121-GFP. Here we further investigated temporal aspects of apoptotic degradation of POM121-GFP. We demonstrate that decreased POM121-GFP fluorescence precedes annexin V-labelling of apoptotic cells. This indicates that degradation of the nuclear pore complex starts prior to redistribution of plasma membrane phosphatidylserine, which serves as a signal for phagocytotic elimination of apoptotic cells. Furthermore, a caspase-resistant GFP-labelled mutant of POM121 resisted degradation even in late apoptosis and was detected in clustered nuclear pores. Thus, it can be concluded that loss of POM121-GFP is a specific sensor of the activation of caspase-3-dependent proteolysis at the nuclear pores.

Ämnesord

NATURVETENSKAP  -- Biologi -- Biokemi och molekylärbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Biochemistry and Molecular Biology (hsv//eng)

NATURVETENSKAP  -- Biologi -- Cellbiologi (hsv//swe)

NATURAL SCIENCES  -- Biological Sciences -- Cell Biology (hsv//eng)

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