Main content area

Tubulin is retained throughout the human hematopoietic/erythroid cell differentiation process and plays a structural role in sedimentable fraction of mature erythrocytes

Nigra, Ayelén D., Santander, Verónica S., Dircio-Maldonado, Roberto, Amaiden, Marina Rafaela, Monesterolo, Noelia E., Flores-Guzmán, Patricia, Muhlberger, Tamara, Rivelli, Juan F., Campetelli, Alexis N., Mayani, Héctor, Casale, Cesar H.
The international journal of biochemistry & cell biology 2017 v.91 pp. 29-36
cell differentiation, drugs, humans, microtubules, paclitaxel, reticulocytes, spectrin, tubulin
We investigated the properties of tubulin present in the sedimentable fraction (“Sed-tub”) of human erythrocytes, and tracked the location and organization of tubulin in various types of cells during the process of hematopoietic/erythroid differentiation. Sed-tub was sensitive to taxol/nocodazole (drugs that modify microtubule assembly/disassembly), but was organized as part of a protein network rather than in typical microtubule form. This network had a non-uniform “connected-ring” structure, with tubulin localized in the connection areas and associated with other proteins. When tubulin was eliminated from Sed-tub fraction, this connected-ring structure disappeared. Spectrin, a major protein component in Sed-tub fraction, formed a complex with tubulin. During hematopoietic differentiation, tubulin shifts from typical microtubule structure (in pro-erythroblasts) to a disorganized structure (in later stages), and is retained in reticulocytes following enucleation. Thus, tubulin is not completely lost when erythrocytes mature; it continues to play a structural role in the Sed-tub fraction.