PKC

PKC Full Name

Protein kinase C

PKC Introduction

Protein kinase C (PKC) represents a family of highly conserved serine/threonine kinases that serve as critical signaling hubs in virtually all eukaryotic cells. Based on their structural domains and specific second-messenger activation requirements, the PKC family is classically divided into three major subfamilies. Conventional PKCs (α, βI, βII, and γ) require both calcium ions and diacylglycerol (DAG) for activation; novel PKCs (δ, ε, η, and θ) require DAG but are calcium-independent; and atypical PKCs (ζ and ι/λ) depend on neither calcium nor DAG, relying instead on other lipid mediators and specific protein-protein interactions.

Figure 1. Cartoon illustrating activation of conventional PKC. (Source: Newton AC. 2018)

Physiologically, PKC functions as a central downstream effector in the phospholipase C (PLC) signaling pathway. Upon the stimulation of cell surface receptors, such as G-protein-coupled receptors or receptor tyrosine kinases, PLC catalyzes the hydrolysis of membrane lipids to generate DAG and release intracellular calcium. These secondary messengers recruit PKC from the cytosol to the plasma membrane, where it undergoes a conformational change and becomes fully active. Once activated, PKC phosphorylates a vast array of cellular substrates, fundamentally regulating cell proliferation, differentiation, apoptosis, cytoskeletal remodeling, and gene transcription. By fine-tuning these diverse cellular processes, PKC maintains tissue homeostasis and orchestrates proper immune and neurological responses. Because PKC isoforms regulate such a broad spectrum of fundamental cellular activities, their structural dysregulation or chronic overactivation is intimately linked to the pathogenesis of numerous severe diseases. In oncology, aberrant PKC signaling can heavily influence cancer progression; importantly, specific PKC isoforms can act as either tumor promoters or tumor suppressors depending entirely on the cellular context and tissue type.

Furthermore, the chronic overactivation of the DAG-PKC signaling axis is a major, well-documented driver of diabetic microvascular complications, including diabetic retinopathy, nephropathy, and neuropathy. This is primarily triggered by the continuous accumulation of DAG induced by sustained hyperglycemia. Additionally, functional imbalances in specific PKC isoforms are heavily associated with cardiovascular pathologies, such as ischemic heart failure and cardiac hypertrophy, as well as complex neurodegenerative conditions like Alzheimer's disease. Consequently, achieving the precise molecular modulation of specific PKC isoforms remains a major focus of ongoing biomedical and pharmacological research.

Alternate Names for PKC

Protein kinase C; PKC

• 1. Newton AC. Protein kinase C: perfectly balanced. Crit Rev Biochem Mol Biol. 2018 Apr;53(2):208-230.
  2. Kaleli HN, et al. Protein Kinase C Isozymes and Autophagy during Neurodegenerative Disease Progression. Cells. 2020 Feb 27;9(3):553.