I got asked this question by a consulting client. Years ago a wise old electrophysiologist who studied one of the ion exchanges in red blood cell (RBC) membranes announced, “Red cells are DEAD cells!” what exactly does this mean? A Moras review answers this question in a more exciting way than most web based answers.
It starts in the bone marrow. We knew that right? And hematopoietic stem cells right? The interseting twist are erythroblast islands with nuclei eating macrophage in the center. [1] The nucleus is the first to go in a process called
Enucleation
Mitochondrial and Mitophagy
As the namesuggests, the mitochondria get eaten. But my whom? By the reticuloxyte itself it would seem. [1] Eating one’s own mitochondria is a pretty normal process that occurs during many different stages of the life of a cell. [3]
Removal of dysfunctional mitochondria is a normal process that is dysfunctional in Prkinson’s Disease.
All other organelles
The Moras review does not go into great details of peroxisome, lysosome, endoplasmic reticulum, ribosome and so on removal. [1] The image that doesn’t reproduce well suggests the whole mess just gets exocytosed into the extracellular environment. WordPress spell check suggests “exorcised” as the correct spelling.
Looking at a few key proteins
- Ctr1 Cu+ channel, absolutely no reference in PubMed
- Na+,K+-ATPase yes, PubMed has plenty to say about this ATP requiring enzyme
- Na+/glucose cotransporter that’s responsible for active transport of glucose does not appear to be in RBC.
- Passive glucose transporters appear to be in RBC membranes
- Glycolysis is part of the RBC “life” from a quick PubMed search.
The Na Pump seems to be there to maintain osmotic balance.
References
- Moras, M., Lefevre, S. D., & Ostuni, M. A. (2017). From Erythroblasts to Mature Red Blood Cells: Organelle Clearance in Mammals. Frontiers in physiology, 8, 1076. PMC free article
- Dorn DC, Dorn A. Stem cell autotomy and niche interaction in different systems. World J Stem Cells. 2015 Jul 26;7(6):922-44 free article
- Ashrafi G, Schwarz TL. (2013) The pathways of mitophagy for quality control and clearance of mitochondria. Cell Death Differ. 2013 Jan;20(1):31-42. free article
