The endocytic vacuoles induced in white ghosts were found to be depleted of spectrin and therefore it was proposed that they arose from spectrin-free areas in the erythrocyte membrane. To follow changes in spectrin distribution during endocytosis, affinity-purified rabbit antispectrin antibodies were produced. Quantitative techniques were developed for the use of a highly specific 125I-F(ab')2 antispectrin, and these showed that before the appearance of vacuoles, as assessed by phase microscopy, there was a reproducible decrease in immunoreactive spectrin. To determine whether this spectrin decrease represented a local or diffuse spectrin loss or a spectrin rearrangement, morphologic studies were undertaken using transmission electron microscopy on samples treated with rabbit antispectrin and ferritin-conjugated goat anti-rabbit immunoglobulin. These studies showed that endocytosis was preceded by the creation of extensive spectrin-free areas separated by discrete spectrin-containing zones. Pretreatment of ghosts with alkaline phosphatase blocked all forms of endocytosis and prevented the creation of spectrin-free areas. Therefore, it is proposed that under the impetus of endocytosis inducers, phosphorylated spectrin is redistributed so that spectrin-free zones are created, and that endocytic vacuoles form and fuse in spectrin-free areas.
Article| September 01 1979
Spectrin rearrangement early in erythrocyte ghost endocytosis.
K G Bensch
S L Schrier
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1979) 82 (3): 654–663.
B Hardy, K G Bensch, S L Schrier; Spectrin rearrangement early in erythrocyte ghost endocytosis.. J Cell Biol 1 September 1979; 82 (3): 654–663. doi: https://doi.org/10.1083/jcb.82.3.654
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