How are proteins transported to lysosomes?

Both classes of proteins are synthesized in the rough ER and transported through the Golgi apparatus to the trans Golgi network. The transport vesicles that deliver these proteins to late endosomes (which later form lysosomes) bud from the trans Golgi network.

Where does palmitoylation occur in the cell?

Protein palmitoylation can occur at the cytoplasmic face of membranes in the secretory pathway (endoplasmic reticulum and Golgi apparatus) and the plasma membrane. PATs catalyze the reaction. These enzymes belong to a family of proteins containing DHHC (Asp-His-His-Cys) cysteine-rich domains (CRD).

What is the purpose of palmitoylation?

Palmitoylation enhances the hydrophobicity of proteins and contributes to their membrane association. Palmitoylation also appears to play a significant role in subcellular trafficking of proteins between membrane compartments,86,87 as well as in modulating protein–protein interactions.

How are lysosomal proteins sorted?

Sorting of cargo receptors and lysosomal transmembrane proteins requires sorting signals present in their cytosolic domains. These signals include dileucine-based motifs, DXXLL or [DE]XXXL[LI], and tyrosine-based motifs, YXXØ, which interact with components of clathrin coats such as GGAs or adaptor protein complexes.

Where is the sorting signal of lysosomal proteins formed?

The Golgi apparatus is known to be the major site of sorting for newly synthesized proteins destined to the lysosomal compartment.

How does a protein move between the Golgi and lysosome?

Protein cargo moves from the ER to the Golgi, is modified within the Golgi, and is then sent to various destinations in the cell, including the lysosomes and the cell surface. The Golgi processes proteins made by the endoplasmic reticulum (ER) before sending them out to the cell.

What does S palmitoylation do to membrane proteins?

By controlling the association of membrane proteins with specific membrane domains/compartments, palmitoylation can bring together, or alternatively segregate, proteins that have the ability to interact under specific circumstances.

Is palmitoylation a post translational modification?

S-palmitoylation is a reversible lipid post-translational modification, involved in different biological processes, such as the trafficking of membrane proteins, achievement of stable protein conformations, and stabilization of protein interactions.

What acts as an address to deliver lysosomal proteins to the lysosome?

Soluble proteins are carried in the lumens of vesicles. Any proteins that are destined for a lysosome are delivered to the lysosome interior when the vesicle that carries them fuses with the lysosomal membrane and joins its contents.

How does protein sorting occur?

From the endoplasmic reticulum, proteins are transported in vesicles to the Golgi apparatus, where they are further processed and sorted for transport to lysosomes, the plasma membrane, or secretion from the cell.

What is the correct pathway of a protein through a cell as it is being made?

These experiments defined a pathway taken by secreted proteins, the secretory pathway: rough ER → Golgi → secretory vesicles → cell exterior. Further studies extended these results and demonstrated that this pathway is not restricted to proteins destined for secretion from the cell.

Is palmitoylation post translational modification?