Golgi to endosome transport

Definition

Target type: biologicalprocess

The directed movement of substances from the Golgi to early sorting endosomes. Clathrin vesicles transport substances from the trans-Golgi to endosomes. [GOC:jl, ISBN:0716731363, PMID:10873832]

Golgi to endosome transport is a crucial step in the intracellular trafficking of proteins and lipids. It involves the movement of vesicles from the Golgi apparatus, the cell's protein sorting and packaging center, to endosomes, which are dynamic organelles involved in sorting and recycling of cellular components. This process is highly regulated and involves various molecular players, including Rab GTPases, SNARE proteins, and adaptor proteins.

The first step in Golgi to endosome transport is the formation of transport vesicles at the trans-Golgi network (TGN). The TGN is the exit site of the Golgi apparatus and serves as a sorting station for proteins and lipids destined for different cellular compartments. Cargo destined for endosomes is packaged into vesicles that bud from the TGN. This budding process is mediated by clathrin-coated vesicles (CCVs) and involves the recruitment of specific adaptor proteins, such as AP-1, which bind to sorting signals on the cargo molecules.

Once the vesicles bud off, they must be transported to the endosomes. This transport is facilitated by motor proteins that move along microtubule tracks. The identity of the motor protein depends on the direction of movement. Dynein motors move vesicles toward the minus end of microtubules, which is typically located at the microtubule organizing center (MTOC), while kinesin motors move vesicles toward the plus end of microtubules, which is often found at the cell periphery.

Upon reaching the endosomes, the transport vesicles fuse with the endosomal membrane. This fusion event is mediated by SNARE proteins. SNARE proteins are specialized transmembrane proteins that reside on the vesicle and target membrane. They interact in a specific manner, forming a complex that brings the two membranes together and promotes their fusion.

The cargo molecules delivered to the endosomes are then sorted for their final destinations. Some molecules are recycled back to the Golgi apparatus or the plasma membrane, while others are targeted for degradation in lysosomes. The sorting process involves various mechanisms, including the interaction of cargo molecules with specific adaptor proteins and the activity of Rab GTPases, which act as molecular switches regulating the recruitment of effector proteins involved in trafficking and fusion.

Overall, Golgi to endosome transport is a complex process involving multiple steps and a diverse array of molecular players. This process plays a critical role in maintaining the proper distribution of proteins and lipids within the cell, contributing to the efficient functioning of various cellular processes.'
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Proteins (1)

Compounds (3)