Death-receptor activation halts clathrin-dependent endocytosis

Area of Science:

• Cell Biology
• Molecular Biology
• Apoptosis Research

Background:

• Endocytosis is vital for maintaining cell homeostasis.
• Proapoptotic death receptors (DRs) play a role in programmed cell death.
• Clathrin-dependent endocytosis is a major pathway for cellular uptake.

Purpose of the Study:

• To investigate the interplay between death receptors and the clathrin-dependent endocytosis machinery.
• To determine how DR stimulation affects endocytosis components.
• To elucidate the role of endocytosis in DR-mediated apoptosis.

Main Methods:

• Stimulation of death receptors (DRs) in cell cultures.
• Analysis of caspase-mediated cleavage of endocytosis proteins.
• Utilizing a temperature-sensitive dynamin-1 mutant to block endocytosis.
• Measuring transferrin uptake as a marker for endocytosis activity.
• Assessing apoptosis levels.

Main Results:

• DR stimulation rapidly triggered caspase-mediated cleavage of key clathrin-pathway components.
• This cleavage halted the cellular uptake of transferrin.
• DR5 internalization via clathrin-mediated endocytosis was observed.
• Blocking endocytosis enhanced DR-induced caspase activation and apoptosis.

Conclusions:

• Death receptor signaling actively disrupts clathrin-dependent endocytosis through caspase activity.
• The internalization of DRs may facilitate caspase-mediated targeting of the endocytic machinery.
• Disruption of clathrin-dependent endocytosis amplifies programmed cell death initiated by DRs.