Protein Sorting 3/29/16 Organelles contain sets of proteins that are specific to their functions What is the function of the following organelles, and what types of proteins might be found in them? Nucleus? Transcription - RNA polymerase Transcription - transcription factor Replication - Mitochondria? ATP synthesis - ATP synthase Golgi? Synthesis of most proteins begins on ribosomes in the cytosol Cytosol - everything inside the cell that is not enclosed by membrane How are proteins delivered to the correct location? Signal sequences direct proteins to the correct compartment Short (15-60 aa) sequence in protein, specifies where it should go Inherent sequence coded for in the DNA information EX- NLS: nuclear localization signal Signal sequences function like zip codes!