Anatomy and Physiology Week 8

This week we went over second messanger systems. In one of the second messanger systems what happens is the protein can't get into the cell, so a message is passed through numerous other proteins in the plasma membrane. They generate a cytoplasmic molecular messanger which will be the protein that activates our protein. The cAMP pathway starts with a collection of associated proteins within the inner surface of the cell membrane. They are always anchored close to the receptor molecule and are called the G protein. There are three subunits, alpha, beta, and gamma. When the protein binds to the receptor a shape change occurs causing the G protein to change shape. This causes the alpha subunit to be released and float to the membrane where it makes contact with another second enzyme causing it to change shape. The second enzyme scoops up ATP molecule and rips off 2 phosphates, leaving one phosphate group(AMP). The enzyme, now activated, releases camp to the cytoplasm which can now bind to PKA ripping off one of its phosphates to bind to another enzyme, and over and over. It is crazy knowing that things this intricate go on in our body on a daily basis. So much has to go right for us to function right.