What Are Protein Kinases?

Kinases are enzymes. They increase the rate proteins are modified by transferring molecules from one protein to another. This activity serves as a signaling mechanism. Protein kinases such as mTOR are crucial to regulating cell signals that control cell function. ^(iii.8, 62)

These types of biochemical signals activate and promote production of proteins critical to multiple cellular processes. An example of this is phosphorylation, which adds a phosphorus molecule to a protein. ^(iii.8, 62)

What Happens if Kinases Are Unregulated?

Aberrations in the expression of these important enzymes can lead to a number of diseases: ^(iii.8, 62)

• Cancer
• Diabetes
• Heart disease
• Neurological disorders
• Obesity
• Rheumatoid arthritis

What Are the Effects of Turmeric Compounds on Protein Kinases?

Curcumin and turmeric both suppress and promote protein kinases. For example, curcumin downregulates mTOR and CDK4 protein kinases. Both of these enzymes promote factors that stimulate cancer cell growth and proliferation. ^{(iii.10, 14, 26, 63, 64)}

On the other hand, curcumin upregulates CHK2, a protein kinase that phosphorylates p53. A tumor suppressor, p53 stimulates production of a protein that inhibits CDK, a kinase involved in the cell growth cycle. This stops the cell from progressing and gives it time to make DNA repairs. If the damage can't be fixed, p53 induces the death of pre-cancerous and malignant cells before they replicate. ^{(iii.10, 14, 26, 63, 64)}

The type of cell involved also dictates curcumin's behavior. For example, in cancer, curcumin suppresses PKA enzymes that trigger the CREB transcription factor involved in tumor cell growth. But in the brain, curcumin stimulates PKA enzymes to protect and keep neuron brain cells healthy. During periods of chronic stress, curcumin inhibits the pCaMKII-type kinases that are over-produced and toxic to brain cells. ^(iii.29)