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Caspase 7-induced cleavage of kinectin in apoptotic cells
T Machleidt1, P Geller, R Schwandner
1Institute of Immunology, Christian-Albrechts University of Kiel, Germany.
Abstract:
Kinectin has been characterized as the first known receptor for the molecular motor kinesin, which is critically involved in microtubule-based vesicle transport and membrane trafficking. Here we identify kinectin as a target for caspase-mediated proteolysis during apoptosis. Treatment of cells with diverse apoptotic stimuli including TNF, anti-Fas, anticancer drugs, gamma-radiation or ceramide leads to rapid proteolytic cleavage of the 160-kDa form of kinectin to a 120-kDa fragment. Evidence is provided that kinectin cleavage is mediated by caspase 7.
Insights
Kinectin, a receptor for kinesin, is cleaved during apoptosis. Caspase 7 mediates this proteolysis, generating a 120-kDa fragment from the 160-kDa kinectin form in response to various apoptotic signals.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Kinectin is identified as the primary receptor for kinesin, a motor protein essential for intracellular transport via microtubules and membrane trafficking.
- Apoptosis, or programmed cell death, involves a cascade of enzymatic reactions, including proteolysis by caspases.
Purpose of the Study:
- To investigate the role of kinectin during apoptosis.
- To identify if kinectin is a substrate for caspase-mediated proteolysis.
- To determine the specific caspase responsible for kinectin cleavage.
Main Methods:
- Treatment of cultured cells with various apoptotic stimuli (TNF, anti-Fas, anticancer drugs, gamma-radiation, ceramide).
- Analysis of protein cleavage using Western blotting or similar techniques to detect changes in kinectin molecular weight.
- In vitro assays or cell-based experiments to confirm the involvement of specific caspases.
Main Results:
- Diverse apoptotic stimuli induce rapid proteolytic cleavage of the 160-kDa kinectin.
- Cleavage results in the formation of a distinct 120-kDa kinectin fragment.
- Evidence strongly implicates caspase 7 as the enzyme responsible for kinectin proteolysis.
Conclusions:
- Kinectin is a novel target for caspase-mediated proteolysis during the apoptotic process.
- Caspase 7 directly cleaves kinectin, contributing to cellular events during apoptosis.
- This finding reveals a new molecular mechanism linking membrane trafficking regulation to programmed cell death.