Question

This protein was discovered when it was shown that certain membrane proteins could be related by a phospholipase that specifically recognized and cleaned inositol-containing phospholipids. A rare type of anemia, paroxysmal nocturnal hemoglobinuria, results from deficiency of this protein and makes red blood cells susceptible to lysis. Which protein is it?

Answer 1

The protein involved in the condition paroxysmal nocturnal hemoglobinuria is the GPI-anchor, which attaches proteins to the cell membrane; its deficiency makes red blood cells lyse more easily.

Step-by-step explanation:

The protein in question is GPI-anchor (glycosylphosphatidylinositol anchor), which is essential for attaching certain proteins to the cell membrane. Phospholipase enzymes can cleave the GPI-anchor leading to the release of the attached protein from the membrane. A deficiency in the GPI-anchor is the cause of the rare anemia known as paroxysmal nocturnal hemoglobinuria (PNH). In PNH, the red blood cells without this protective anchor become more susceptible to lysis, which means they are more easily destroyed. This destruction of red blood cells leads to hemoglobin being released into the blood, hence the term hemoglobinuria, where hemoglobin is found in the urine, particularly noticed following a night's sleep (hence nocturnal).