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Role of protein kinase activity in apoptosis
1Cancer Research Unit, Queensland Institute of Medical Research, Bancroft Centre, PO Royal Brisbane Hospital, Herston, Australia.
Abstract:
The transmission of signals from the plasma membrane to the nucleus involves a number of different pathways all of which have in common protein modification. The modification is primarily in the form of phosphorylation which leads to the activation of a series of protein kinases. It is now evident that these pathways are common to stimuli that lead to mitogenic and apoptotic responses. Even the same stimuli under different physiological conditions can cause either cell proliferation or apoptosis. Activation of specific protein kinases can in some circumstances protect against cell death, while in others it protects the cell against apoptosis. Some of the pathways involved lead to activation of transcription factors and the subsequent induction of genes involved in the process of cell death or proliferation. In other cases, such as for the tumour suppressor gene product p53, activation may be initiated both at the level of gene expression or through pre-existing proteins. Yet in others, while the initial steps in the pathway are ill-defined, it is clear that downstream activation of a series of cystein proteases is instrumental in pushing the cell towards apoptosis. In this report we review the involvement of protein kinases at several different levels in the control of cell behaviour.
Insights
Cell signaling pathways, primarily involving protein kinases and phosphorylation, control cell proliferation and apoptosis. These pathways are crucial for cellular responses to various stimuli, influencing cell fate.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- Signal transduction pathways transmit information from the cell surface to the nucleus.
- Protein modification, particularly phosphorylation, is a common mechanism in these pathways.
- These pathways are implicated in both mitogenic (cell proliferation) and apoptotic (programmed cell death) responses.
Purpose of the Study:
- To review the role of protein kinases in regulating cell behavior.
- To explore how signaling pathways control cell fate decisions (proliferation vs. apoptosis).
- To examine the involvement of protein kinases in diverse cellular responses.
Main Methods:
- Literature review of signaling pathways.
- Analysis of protein kinase involvement in cell fate determination.
- Examination of transcription factor activation and gene expression.
Main Results:
- Protein kinases are central to signal transduction, mediating responses to mitogenic and apoptotic stimuli.
- The same stimuli can induce either proliferation or apoptosis depending on physiological context.
- Protein kinase activation can either protect against or promote apoptosis.
- Pathways involve transcription factors, p53 regulation, and cysteine proteases.
Conclusions:
- Protein kinases play multifaceted roles in controlling cell behavior, from proliferation to apoptosis.
- Understanding these pathways is key to deciphering cell fate decisions.
- Protein kinases are critical regulators at multiple levels of cellular control.