CFLAR (CASP8 and FADD-like Apoptosis Regulator) Protein
Overview
CFLAR (also known as c-FLIP, Cellular FLICE-like Inhibitory Protein) is a master regulator of [extrinsic apoptosis](/mechanisms/extrinsic-apoptosis) and [necroptosis](/mechanisms/necroptosis) that plays a critical role in determining cell survival or death in [neurons](/cell-types/neurons). This protein is particularly important in [neurodegenerative diseases](/diseases/neurodegeneration) where dysregulated [cell death pathways](/mechanisms/cell-death-pathways) contribute to neuronal loss.
<div class="infobox infobox-protein">
| Property | Value | |----------|-------| | Protein Name | CFLAR (Cellular FLICE-like Inhibitory Protein) | | Gene | [CFLAR](/genes/cflar) | | UniProt ID | O15519 | | PDB IDs | 2RJ8, 3H11, 4ZGM | | Molecular Weight | 55-60 kDa (isoform dependent) | | Subcellular Localization | Cytoplasm, nucleus | | Protein Family | Death effector domain (DED) family | | Aliases | c-FLIP, FLICE-inhibitory protein, Usurpin |
</div>
Structure
CFLAR is structurally similar to [caspase-8](/proteins/caspase-8) but lacks catalytic activity. The protein contains:
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CFLAR Protein
title: CFLAR Protein
CFLAR (CASP8 and FADD-like Apoptosis Regulator) Protein
Overview
CFLAR (also known as c-FLIP, Cellular FLICE-like Inhibitory Protein) is a master regulator of [extrinsic apoptosis](/mechanisms/extrinsic-apoptosis) and [necroptosis](/mechanisms/necroptosis) that plays a critical role in determining cell survival or death in [neurons](/cell-types/neurons). This protein is particularly important in [neurodegenerative diseases](/diseases/neurodegeneration) where dysregulated [cell death pathways](/mechanisms/cell-death-pathways) contribute to neuronal loss.
<div class="infobox infobox-protein">
| Property | Value | |----------|-------| | Protein Name | CFLAR (Cellular FLICE-like Inhibitory Protein) | | Gene | [CFLAR](/genes/cflar) | | UniProt ID | O15519 | | PDB IDs | 2RJ8, 3H11, 4ZGM | | Molecular Weight | 55-60 kDa (isoform dependent) | | Subcellular Localization | Cytoplasm, nucleus | | Protein Family | Death effector domain (DED) family | | Aliases | c-FLIP, FLICE-inhibitory protein, Usurpin |
</div>
Structure
CFLAR is structurally similar to [caspase-8](/proteins/caspase-8) but lacks catalytic activity. The protein contains:
Two Death Effector Domains (DEDs): The N-terminal DEDs mediate interactions with [FADD](/proteins/fadd-protein) and [caspase-8](/proteins/caspase-8) at the DISC (Death-Inducing Signaling Complex)
Multiple Splice Variants:
c-FLIP_L (long isoform): Full-length form with two DEDs
Dual role: Can both promote and inhibit autophagy depending on cellular context
Necroptosis Inhibition
CFLAR blocks the [necroptosis pathway](/mechanisms/necroptosis) by:
Inhibiting RIPK1 activation: Prevents formation of the necrosome
Modulating RIPK3 interactions: Affects MLKL recruitment and activation
Role in Neurodegeneration
Alzheimer's Disease
In [Alzheimer's disease](/diseases/alzheimers-disease), CFLAR expression is modulated by [amyloid-beta](/proteins/amyloid-beta) toxicity:
Amyloid-beta induced upregulation: [Neurons](/entities/neurons) increase c-FLIP expression as a protective response [3]
Anti-apoptotic function: c-FLIP protects against Aβ-induced caspase-8 activation [4]
Therapeutic implications: Enhancing c-FLIP expression may provide neuroprotection
Parkinson's Disease
In [Parkinson's disease](/diseases/parkinsons-disease), CFLAR protects [dopaminergic neurons](/cell-types/dopaminergic-neurons):
Protection against MPTP toxicity: c-FLIP overexpression protects against MPTP-induced parkinsonism [5]
Modulation of mitochondrial apoptosis: Interacts with Bcl-2 family proteins
DJ-1 interaction: Partners with DJ-1 (parkinsonism-associated protein) in neuroprotection
Stroke and Ischemia
Following cerebral ischemia:
Ischemic preconditioning: Upregulation of c-FLIP mediates neuroprotection [6]
Reperfusion injury: Modulates death receptor signaling during reperfusion
Therapeutic window: Timing of c-FLIP modulation critical for outcomes
Amyotrophic Lateral Sclerosis (ALS)
In [ALS](/diseases/amyotrophic-lateral-sclerosis):
Altered expression patterns: c-FLIP levels changed in motor neuron disease
Excitotoxicity modulation: Links glutamate excitotoxicity to apoptosis
SOD1 mutations: Interaction with mutant SOD1 toxicity pathways
Multiple Sclerosis
CFLAR contributes to [neuroinflammation](/mechanisms/neuroinflammation) regulation:
Microglial activation: Modulates microglial cell death decisions
T-cell survival: Affects immune cell viability in CNS autoimmunity
Therapeutic Relevance
Targeting CFLAR in Neurodegeneration
Modulating CFLAR represents a therapeutic strategy:
Neuroprotective agents: Compounds that upregulate c-FLIP expression
Combination therapies: c-FLIP modulation with other anti-apoptotic proteins
Drug development: Small molecules targeting FLIP-caspase-8 interactions
Cancer Relevance (parallels for neurodegeneration)
While CFLAR is extensively studied in cancer (where high expression confers chemoresistance), the same anti-apoptotic mechanisms that make it a cancer therapeutic target make it relevant for neuroprotection [7].