Final answer:
NF-kB is a transcription factor kept inactive by the inhibitor IK-B. Phosphorylation of IK-B by PKC releases NF-kB, allowing it to enter the nucleus and initiate gene transcription, thereby regulating immune response, inflammation, and apoptosis.
Step-by-step explanation:
NF-kB and Its Role in Transcription Regulation
NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) is a protein complex that functions as a transcription factor in cells. It plays a crucial role in regulating the immune response to infection by controlling the expression of genes involved in inflammation, immune response, cell growth, and apoptosis. NF-kB is kept in an inactive state in the cytoplasm by an inhibitor protein called IK-B. When IK-B is phosphorylated by another protein kinase such as PKC (protein kinase C), NF-kB is released and can enter the nucleus to initiate RNA transcription and the production of proteins.
Activation Cycle of NF-kB
The phosphorylation of IK-B leads to its dissociation from NF-kB, freeing NF-kB to enter the nucleus and stimulate the transcription of target genes. This increase in cellular metabolism and gene expression plays a significant role in the growth and survival of the cell, and under certain conditions, can also induce apoptosis.