Question

Rab5-GTP recruits PI 3-Kinase. PI(3)P can recruit Rab5-GEF. More Rab5-GEF makes more active Rab5-GDP.

A) Signaling pathways in the cytoplasm
B) Regulation of membrane trafficking in early endosomes
C) Cellular responses to oxidative stress
D) Protein synthesis in the endoplasmic reticulum

Answer 1

The question focuses on the biological process of regulating membrane trafficking in early endosomes through a sequence of interactions involving Rab5-GTP, PI 3-Kinase, and Rab5-GEF.

Step-by-step explanation:

The sequence of events starting with Rab5-GTP recruiting PI 3-Kinase and culminating in the generation of more active Rab5-GDP via PI(3)P and Rab5-GEF is indicative of a biochemical process related to regulation of membrane trafficking in early endosomes. This process is a critical component of endocytic pathways, where cells internalize various molecules and particulates from their environment. Rab5-GTP is a GTPase acting as a molecular switch in the regulation of endosome dynamics, and its recruitment of PI 3-Kinase leads to the production of PI(3)P, a phospholipid that marks organelles for specific functions and selectively recruits effector proteins like Rab5-GEF, which in turn activates more Rab5, hence perpetuating the process.