Membrane perturbations of erythrocyte ghosts by spectrin release.
The cytoskeleton plays an important role in the stability and function of the membrane. Spectrin release from erythrocyte ghosts makes the membrane more fragile. However, the detail of membrane fragility has remained unclear. In the present study, the effects of incubation temperatures and polyamines on the membrane structure of ghosts under hypotonic conditions have been examined. Upon exposure of ghosts to a hypotonic buffer at 0-37 degrees C, reduction of ghost volume, spectrin release and decrease of band 3-cytoskeleton interactions were clearly observed above 30 degrees C. However, such changes were completely inhibited by spermine and spermidine. Interestingly, conformational changes of spectrin induced at 37 degrees C or 49 degrees C were not suppressed by both polyamines. Flow cytometry of fluorescein isothiocyanate-labelled ghosts exposed to 37 degrees C demonstrated the two peaks corresponding to ghosts with normal spectrin content and decreased one. Taken together, these results indicate that the degree of spectrin release from the membrane under hypotonic conditions is not same in all ghosts, and that polyamines inhibit the spectrin release followed by changes in the membrane structure, but not conformational changes of spectrin.
Yamaguchi
Takeo
T
Department of Chemistry, Faculty of Science, Fukuoka University, Jonan-ku, Fukuoka 814-0180, Japan. takeo@fukuoka-u.ac.jp
Ozaki
Shinnosuke
S
Shimomura
Taiji
T
Terada
Shigeyuki
S
D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D005434:Flow Cytometry; D006801:Humans; D007038:Hypotonic Solutions / Q000494:pharmacology; D011073:Polyamines / Q000494:pharmacology; D011487:Protein Conformation / Q000187:drug effects; D013049:Spectrin / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D013696:Temperature
D001457:Anion Exchange Protein 1, Erythrocyte; D007038:Hypotonic Solutions; D011073:Polyamines; D013049:Spectrin