Identification of ubiquitinated repeats in human erythroid alpha-spectrin.
The spectrin role(s) is (are) very important for the shape and the physical properties of red cells, such as deformability and resistance to mechanical stresses. Moreover a variety of spectrin diseases are known. We have previously demonstrated [Corsi, D., Galluzzi, L., Crinelli, R. & Magnani, M. (1995) J. Biol. Chem. 270, 8928-8935] that human erythroid alpha-spectrin is ubiquitinated in vitro and in vivo. In order to define the ubiquitinated repeats of this long protein and find out a possible function, we have produced recombinant peptides encompassing the alphaIII-, alphaIV-, alphaV- and EF hand domains of alpha-spectrin chain. These peptides were tested in in vitro ubiquitin conjugation assays and two regions susceptibles to ubiquitination were found. The first one, in the alphaIV-domain, includes the repeat 17 and the second one, in the alphaV-domain, includes the repeat 20 and a part of repeat 21. We also demonstrated that the susceptibility to ubiquitination of the alphaV-domain is reduced by interaction with the corresponding portion of beta-spectrin chain (betaIV-domain). Thus, at least ubiquitination of alphaV-domain is susceptible to cytoskeleton assembly and spectrin dimerization.
Galluzzi
L
L
Institute of Biological Chemistry 'G. Fornaini', University of Urbino, Italy.
Nicolas
G
G
Paiardini
M
M
Magnani
M
M
Lecomte
M C
MC
D001483:Base Sequence; D017931:DNA Primers; D006801:Humans; D011994:Recombinant Proteins / Q000737:chemistry; D020449:Repetitive Sequences, Amino Acid; D013049:Spectrin / Q000737:chemistry*; D014452:Ubiquitins / Q000737:chemistry*
D017931:DNA Primers; D011994:Recombinant Proteins; D014452:Ubiquitins; D013049:Spectrin