Activation of protein kinase-C causes
**Core Concept**
Activation of protein kinase-C (PKC) is a crucial step in the signaling pathway of various cellular processes, including cell proliferation, differentiation, and survival. PKC is a family of serine/threonine kinases that play a significant role in cellular responses to external signals, such as hormones, growth factors, and neurotransmitters.
**Why the Correct Answer is Right**
Upon activation, PKC catalyzes the phosphorylation of various downstream targets, leading to the modulation of cellular functions. PKC activation is often triggered by the increase in intracellular calcium concentrations, which in turn activates phospholipase C (PLC). PLC catalyzes the hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2) to form diacylglycerol (DAG) and inositol 1,4,5-trisphosphate (IP3). DAG then activates PKC by binding to its regulatory domain, leading to the translocation of PKC to the membrane and its subsequent activation.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect as it does not accurately describe the consequence of PKC activation. While PKC does regulate various cellular processes, its activation does not directly lead to the inhibition of protein synthesis.
**Option B:** This option is incorrect as it is a downstream effect of PKC activation, not a direct consequence. The activation of MAPK/ERK pathway is a result of PKC's downstream signaling, but it is not the primary effect of PKC activation.
**Option C:** This option is incorrect as it describes a different signaling pathway altogether. The activation of AMP-activated protein kinase (AMPK) is a response to cellular energy stress, which is unrelated to PKC activation.
**Clinical Pearl / High-Yield Fact**
PKC has been implicated in various diseases, including cancer, cardiovascular disease, and neurological disorders. Its dysregulation can lead to the development and progression of these diseases, highlighting the importance of understanding PKC's signaling pathways in the context of human disease.
**Correct Answer:** C.