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.

INTERNATIONAL JOURNAL OF BIOCHEMISTRY AND CELLULAR BIOLOGY

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2017 vol. 91 p. 29 - 36

1357-2725

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.