Protein kinase C (PKC)

Definition

Protein kinase C (PKC) is a family of serine/threonine kinases that play crucial roles in various cellular processes, including cell growth, differentiation, and apoptosis. PKC is activated by various hormones and growth factors, which lead to a cascade of signaling events that can influence metabolic pathways, gene expression, and other critical cellular functions.

5 Must Know Facts For Your Next Test

1. PKC is activated by diacylglycerol (DAG) and calcium ions, which are often generated in response to hormone signaling.
2. Different isoforms of PKC exist, each with unique functions and tissue distributions, allowing for diverse regulatory roles in cellular processes.
3. PKC is involved in the regulation of various biological functions, including inflammation, immune responses, and insulin signaling.
4. Aberrant PKC activity has been implicated in various diseases, including cancer and diabetes, making it a potential therapeutic target.
5. PKC signaling can influence gene expression by modulating transcription factors, thus impacting cellular behavior and function.

Review Questions

• How does protein kinase C (PKC) relate to hormone signaling and what role does it play in cellular responses?
  • Protein kinase C (PKC) is directly involved in hormone signaling as it is activated by second messengers like diacylglycerol (DAG) and calcium ions that are produced in response to hormone binding. Once activated, PKC initiates a cascade of phosphorylation events that lead to various cellular responses such as growth, differentiation, and metabolic changes. This mechanism shows how PKC serves as a critical link between extracellular signals and intracellular actions.
• Discuss the different isoforms of PKC and their significance in physiological processes.
  • There are several isoforms of protein kinase C (PKC), each having distinct roles depending on the tissue type and cellular context. For instance, PKC-alpha is often associated with cell proliferation and survival while PKC-beta plays a significant role in immune responses. The diversity among isoforms allows PKC to fine-tune its regulatory effects on various physiological processes like inflammation and insulin signaling, showcasing its importance in maintaining homeostasis.
• Evaluate the implications of dysregulated PKC activity in diseases such as cancer and diabetes.
  • Dysregulation of protein kinase C (PKC) activity can contribute to disease progression in conditions like cancer and diabetes. In cancer, aberrant PKC signaling may promote uncontrolled cell proliferation and survival by altering gene expression through its phosphorylation effects on transcription factors. In diabetes, improper PKC function can disrupt insulin signaling pathways, leading to insulin resistance. Understanding these mechanisms opens avenues for potential therapeutic strategies targeting PKC to restore normal cellular functions and treat these diseases.

Related terms

Second Messenger: Small molecules or ions that relay signals received from receptors on the cell surface to target molecules inside the cell, amplifying the signal.

Phosphorylation:

The addition of a phosphate group to a protein or other organic molecule, which can alter the function or activity of the molecule.

Signal Transduction Pathway: A series of molecular events and reactions that transmit signals from a receptor on the cell surface to elicit a response inside the cell.