Tissue-specific analogues of erythrocyte protein 4.1 retain functional domains.
Analogues of the human erythroid membrane skeletal component protein 4.1 have been identified in perfused rat tissues and human T and B lymphocyte cell lines. olyclonal antibodies were used which are specific for all domains of protein 4.1, the spectrin-actin-promoting 8-Kd peptide, the membrane-binding 30-Kd domain, and the 50-Kd domain. Antibody reactivity, by Western blotting of tissue homogenates, shows reactivity with proteins varying in molecular weight from 175 Kd to 30 Kd. Further, these protein 4.1 analogues appear to be expressed in a tissue-specific fashion. Of the analogues detected there appear to be at least three classes: analogues containing all erythroid protein 4.1 domains, analogues containing all domains but with modified antigenic epitopes, and analogues containing only some domains. Chemical cleavage at cysteine linkages indicates that in analogues containing the 30-Kd region the location of cysteine is highly conserved. This datum suggests that in nonerythroid 4.1 isoforms of higher molecular weight the additional protein mass is added to the amino terminal end (30 Kd end).
Anderson
R A
RA
Department of Pathology, Yale University of Medicine, New Haven, Connecticut 06510.
Correas
I
I
Mazzucco
C
C
Castle
J D
JD
Marchesi
V T
VT
D000818:Animals; D001923:Brain Chemistry; D003598:Cytoskeletal Proteins; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D007120:Immunochemistry; D008565:Membrane Proteins / Q000032:analysis*; D008970:Molecular Weight; D009479:Neuropeptides; D009928:Organ Specificity; D010306:Parotid Gland / Q000032:analysis; D051381:Rats; D011919:Rats, Inbred Strains
D003598:Cytoskeletal Proteins; D008565:Membrane Proteins; D009479:Neuropeptides; C028841:erythrocyte membrane band 4.1 protein; C120557:erythrocyte membrane protein band 4.1-like 1