User:Gbgaski/Intracellular transport

Intracellular transport
Intracellular transport is unique to eukaryotic cells because they possess organelles enclosed in membranes that need to be mediated for exchange of cargo to take place. Intracellular transport is required for maintaining homeostasis within the cell by responding to physiological signals. Proteins synthesized in the cytosol are distributed to their respective organelles, according to their specific amino acid’s sorting sequence.

Fusion
Rab proteins on the surface of the transport vesicle are responsible for aligning with the complementary tethering proteins found on the respective organelle's cytosolic surface. This fusion event allows for the delivery of the vesicles contents mediated by proteins such as SNARE proteins. The endoplasmic reticulum serves as a channel that proteins will pass through bound for their final destination. Outbound proteins from the ER will use transport vesicles to travel along the cell cortex to reach their specific destinations.

Role of microtubules
Motor proteins connect the transport vesicles to microtubules and actin filaments to facilitate intracellular movement. The transport mechanism depends on the material being moved. Intracellular transport that requires quick movement will use an actin-myosin mechanism while more specialized functions require microtubules for transport.