Question

Protein Trafficking

- What are the options for where proteins are synthesized?

- What are the organelles involved in protein trafficking?

- What is the pathway of a protein meant to be in the plasma membrane? What about on

the membrane of an organelle? What about an extracellular signal? What about a

lysosome or peroxisome?

- What tells the protein where its destination is?

Answer 1

1. Proteins synthesis occur in cellular structures called ribosomes. They are complex structures found floating into the cytoplasm or attached to the endoplasmic reticulum. The ribosomes receives their command for protein synthesis from nucleus where the DNA is transcribed into messenger RNA. Protein synthesis is a multi step process used to manufacture a protein molecule. The first step is transcription during which the information encoded in the DNA is copied to a messenger RNA sequence (mRNA). The second step is called translation.

2. Protein trafficking is referred to as transport and movement of proteins throughout the cell or from the cell to the extracellular matrix.

The main organelle involved in protein trafficking is the Golgi apparatus. The proteins that have been translated by the endoplasmic reticulum are first carried to Golgi apparatus through specialised vehicles called vesicles. Within the Golgi body the proteins are modified and sorted depending upon their final destination.