In the long-term pathway of insulin signaling, which molecule activates gene expression?

In the long-term pathway of insulin signaling, the activation of gene expression primarily involves the Ras protein. Upon insulin binding to its receptor, a series of downstream signaling cascades are initiated. The receptor activates insulin receptor substrates (IRS), which in turn activate the Ras pathway among others.

Ras is a small GTPase that, when activated, triggers the MAPK/ERK signaling pathway. This pathway ultimately leads to the activation of transcription factors that move into the nucleus and promote the expression of genes involved in glucose metabolism, cell growth, and differentiation. This process plays a crucial role in the long-term effects of insulin, including promoting cellular growth and regulating metabolic processes.

The other molecules listed play different roles in insulin signaling. For instance, cAMP is more associated with pathways involving glucagon rather than directly with the long-term effects of insulin. PIP2 acts as a precursor to second messengers like inositol trisphosphate and diacylglycerol, which signal short-term effects of insulin rather than gene expression. Protein kinase B (Akt) is also involved in insulin signaling but is primarily associated with effects like glucose uptake and metabolism rather than direct gene activation. Therefore, Ras is key to the long-term activation of gene expression following