Question

What enzyme does PIP3 activate in the insulin pathway?

a) Protein kinase A (PKA)
b) Phosphoinositide 3-kinase (PI3K)
c) Mitogen-activated protein kinase (MAPK)
d) Glycogen synthase kinase 3 (GSK-3)

Answer 1

PIP3 activates Protein Kinase B (PKB/AKT) in the insulin pathway, which is essential for glucose uptake and glycogen synthesis. This action was not explicitly listed among the provided choices, which may indicate a typo or confusion.

Step-by-step explanation:

The enzyme that PIP3 activates in the insulin pathway is Protein Kinase B (PKB) also known as AKT, which is not listed as an option in the provided choices.

However, under the assumption that this might be a typo or confusion in the given choices, the closest answer would be Phosphoinositide 3-kinase (PI3K) which is involved earlier in the pathway where it helps to produce PIP3 by phosphorylating PIP2. However, PI3K itself is not activated by PIP3, but rather it is responsible for the production of PIP3. Protein kinase B (PKB/AKT), once activated by PIP3, plays a crucial role in the insulin signaling pathway that affects glucose uptake and glycogen synthesis, among other functions.