No, I am not directly talking dietary fats, although these macromolecules really get a bad reputation. Plasma membrane lipids. I am finding it really tough to write broad sweeping statements like “Plasma membrane lipids are variable and dynamic”….without thinking about all the great facts about these lovely little amphipathic structures.
As I was writing my course pack notes today I decided that I need to give the plasma membrane lipids a little bit of spot light (okay….maybe an entire lecture). Did you know that the little phospholipid cartoon that we draw in first year classes are more than just a hydrophilic head and a hydrophobic tail?? These phospholipids have unique polar heads (-inositol, serine, choline and ethanolamine), which can be added to a glycerolphospholipid or a sphingolipid. The typical fatty acid tails (2 on each phospholipid) are also variable, being usually 16 to 18 carbons in length, saturated (no double bonds) or unsaturated (1 or more double bonds). The types of fatty acids incorporated into our plasma membrane is dependent on our diets. More unsaturated fatty acids (think olive oil), the more fluid our membranes, changing the functionality. Science is booming in the land of lipids. From nutritional sciences to the effects of obesity on the physiology of a number of organs. With the rise of obesity, it is becoming even more important that we understand how dietary lipids can change the function of literally every plasma membrane in our body for the good or the bad.
Have I turned you into a lipid lover? Here is a fantastic review that highlights just some of the really interesting complexities that exist in that seemingly innocent looking plasma membrane lipid.
Image from: Holthuis JCM, Levine TP. “Lipid Trafficking: Floppy Drives and a Super Highway” Nature Reviews Molecular Cell Biology, 2005 Mar;6(3):209-220.