AP BIOLOGY

Detailed explanation-1: -The activated G-protein next binds to cytoplasmic protein kinase which activates the kinase’s phosphorylation activity. The kinase can then send a signal via phosphorylation. The final step would be the activation of transcription via a nuclear transcription factor.

Detailed explanation-2: -Transcription factors (TFs) are key regulators of intrinsic cellular processes, such as differentiation and development, and of the cellular response to external perturbation through signaling pathways. In this review we focus on the role of TFs as a link between signaling pathways and gene regulation.

Detailed explanation-3: -Many signaling pathways ultimately regulate protein synthesis, usually by turning specific genes on or off in the nucleus. Like an activated steroid receptor, the final activated molecule in a signaling pathway may function as a transcription factor.

Detailed explanation-4: -Transcription factor activation is complex and may involve multiple intracellular signal transduction pathways, including the kinases PKA, MAPKs, JAKs, and PKCs, stimulated by cell-surface receptors [8, 9]. Transcription factors may also be directly activated by ligands such as glucocorticoids and vitamins A and D [5].

Detailed explanation-5: -In many cases, genes that are transcribed as a result of these signaling molecules are themselves transcription factors that can combine to activate subsequent rounds of transcription of a completely different set of genes.