Stochastic Model of Maturation and Vesicular Exchange in Cellular Organelles

TL;DR

This paper presents a stochastic model demonstrating how membrane-bound organelles mature and exchange vesicles, highlighting the significance of maturation in organelle dynamics, especially in small organelles like endosomes and Golgi cisternae.

Contribution

It introduces a stochastic framework to analyze organelle maturation versus vesicular exchange, clarifying their roles in organelle dynamics.

Findings

Full maturation can be modeled as stochastic escape from a steady state.

Maturation significantly contributes to out-flux in small organelles.

Vesicular exchange dominates in certain steady-state conditions.

Abstract

The dynamical organization of membrane-bound organelles along intracellular transport pathways relies on vesicular exchange between organelles and on biochemical maturation of the organelle content by specific enzymes. The relative importance of each mechanism in controlling organelle dynamics remains controversial, in particular for transport through the Golgi apparatus. Using a stochastic model, we show that full maturation of membrane-bound compartments can be seen as the stochastic escape from a steady-state in which export is dominated by vesicular exchange. We show that full maturation can contribute a significant fraction of the total out-flux for small organelles such as endosomes and Golgi cisternae.