cellular compartments

• Nucleus

  DNA Storage
• Mitochondrion


  Energy production
• Smooth endoplasmic reticulum (SER)

  Lipid production; Detoxification
• Rough endoplasmic reticulum (RER)


  Protein production; in particular for export out of the cell
• Golgi apparatus


  Protein modification and export
• Peroxisome


  Lipid Destruction; contains oxidative enzymes
• Lysosome


  Protein destruction
• Protein trafficking


  Is a process of transporting specific proteins into different organelles or nucleus with the help of signal peptides
• Protein sorting signals


  Are route proteins to the correct subcellular compartment. It also regulates protein trafficking to plasma membrane domains
• Nuclear proteins are actively transported into the nucleus while RNA molecules and newly made ribosomal subunits contain nuclear export signals that direct their active transport outward through the pore complexes
• GTP hydrolysis and nuclear transport

  Support formation of complexes containing an export receptor and cargos such as RNAs, RNPs or proteins that are destined for export
• Orientation of the transport

  When this vesicle fuses with the plasma membrane, the N-terminus of Krt1 will be in the extracellular space
• Vesicular transport


  Is responsible for molecular traffic between a variety of specific membrane-enclosed compartments
• Mutations in the proteins

  Alter protein structure and disrupt trafficking of the protein (the "cargo")
• The function of clathrin proteins is shaping rounded vesicles in the cytoplasm for intracellular trafficking
• Correct vesicle sorting, fission, transport, tethering, docking and fusion are the function of Rab proteins
• SNARE proteins

  Mediate the fusion of vesicles with the target membrane; this mediates exocytosis, but cam also mediate the fusion of vesicles with membrane-bound compartments (ex. lysosome)
• Phagocytosis


  Is the ingestion of large particles such as cell debris and whole microorganisms by means of large vesicles (cell eating)
• Pinocytosis

  Is the internalization of extracellular fluid and small macromolecules by means of small vesicles (cell drinking)
• Receptor mediated endocytosis


  Receptor proteins on the cell surface are used to capture a specific target molecule
• Example of cholesterol with receptor of mediated endocytosis not working


  If receptor is not working, it doesn't detect input which leads to harm. Failure to uptake cholesterol results in its deposition in the blood vessels which causes a heart attack