Ca2(+)-dependent membrane-binding proteins in normal erythrocytes and
erythrocytes from patients with chronic myelogenous leukemia
M Fujimagari, PL Williamson and RA Schlegel
Department of Molecular and Cell Biology, Pennsylvania State University,
University Park 16802.
Cytosolic and membrane fractions of human erythrocytes were probed with
antisera raised against several members of the annexin family of Ca2(+)-
dependent phospholipid/membrane-binding proteins. One of the antisera, that
against the 67 Kd calcimedin, identified erythrocyte polypeptides of
molecular weights 48 and 67 Kd, which were found in the cytoplasm when
normal erythrocytes were lysed in the presence of EGTA but on the membrane
when lysis buffers contained Ca2+. In contrast, membranes of erythrocytes
from patients with chronic myelogenous leukemia (CML) contained the 67 Kd
protein even when prepared in the absence of Ca2+, as well as the
antibody-reactive proteins of 35 and 38 Kd. When prepared in the presence
of Ca2+, CML membranes contained increased levels of these three species
and the 48 Kd protein, as well. These results suggest that normal
erythrocytes contain a calcimedin-like protein that is translocated to the
membrane in the presence of Ca2+ and that CML erythrocytes have both an
abnormal amount and distribution of calcimedin-like proteins.
Volume 75,
Issue 6,
pp. 1337-1345,
03/15/1990
Copyright © 1990 by The American Society of Hematology
