Calcium-dependent proteolysis of actin during storage of platelet concentrates.
In an ongoing study of the changes that occur in platelet concentrates during storage, we investigated two 28-26-Kd proteins designated SP-1 and SP-2, respectively, which increase markedly during blood-bank storage of platelet concentrates at room temperature. Formation of SP-1 and SP-2 was inhibited by storage at 4 degrees C as well as by treatment of the concentrates with leupeptin, N-ethylmaleimide, and EDTA; DFP and PPACK had no effect. The calcium ionophore A23187 markedly stimulated production of SP-1 and SP-2. After partial purification, the two proteins were found to be associated with platelet cytoskeletal protein. Two-dimensional peptide mapping and amino acid sequencing identified SP-1 and SP-2 as fragments of actin formed by cleavage on the N-terminal side of residues Thr-106 and Ala-114, respectively. Generation of SP-1 and SP-2 during storage of platelet concentrate is likely attributable to calcium-dependent neutral protease degradation of actin and may have implications for development of the platelet storage lesion.
Snyder
E L
EL
Department of Laboratory Medicine, Yale University School of Medicine, New Haven, CT 06504.
Horne
W C
WC
Napychank
P
P
Heinemann
F S
FS
Dunn
B
B
D000199:Actins / Q000302:isolation & purification / Q000378:metabolism*; D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000201:enzymology / Q000378:metabolism* / Q000502:physiology; D001793:Blood Preservation; D001798:Blood Proteins / Q000096:biosynthesis / Q000302:isolation & purification; D002118:Calcium / Q000502:physiology*; D003598:Cytoskeletal Proteins / Q000097:blood; D006801:Humans; D006868:Hydrolysis; D008969:Molecular Sequence Data; D010447:Peptide Hydrolases / Q000502:physiology*; D010449:Peptide Mapping; D011480:Protease Inhibitors; D013696:Temperature
D000199:Actins; D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D011480:Protease Inhibitors; D010447:Peptide Hydrolases; D002118:Calcium