Ca2+-mediated catabolism of human erythrocyte band 3 protein.
Catabolism of human erythrocyte membrane band 3 protein in the presence of Ca2+ was studied. An increase in the amount of a 30 kDa amino terminal fragment of band 3 was observed when erythrocyte membranes were incubated for 30 min with 1 mM Ca2+ in the presence of whole erythrosol. Incubation of the membranes with Ca2+ alone did not result in band 3 breakdown. Generation of the 30 kDa fragment from band 3 was related to the action of a leupeptin-sensitive Ca2+-dependent proteinase in the cytosol. This proteinase was also responsible for the increased production of a 52 kDa and a 70 kDa transmembrane carboxyl terminal fragment of band 3. From the size of the generated fragments, it is deduced that in the presence of Ca2+ and Ca2+-dependent proteinase, band 3 protein is cleaved at the cytoplasm/membrane interface and along its cytoplasmic domain.
Au
K S
KS
Department of Biochemistry, University of Hong Kong.
Hsu
L
L
Morrison
M
M
D001457:Anion Exchange Protein 1, Erythrocyte / Q000378:metabolism*; D002118:Calcium / Q000494:pharmacology*; D002154:Calpain / Q000097:blood; D004591:Electrophoresis, Polyacrylamide Gel; D004912:Erythrocytes / Q000378:metabolism*; D006801:Humans; D007976:Leupeptins / Q000494:pharmacology; D008970:Molecular Weight
D001457:Anion Exchange Protein 1, Erythrocyte; D007976:Leupeptins; D002154:Calpain; C032854:leupeptin; D002118:Calcium