Erythroid spectrin, brain fodrin, and intestinal brush border proteins (TW-260/240) are related molecules containing a common calmodulin-binding subunit bound to a variant cell type-specific subunit.
Spectrin, fodrin, and TW-260/240 form a group of structurally and functionally similar but not identical high molecular weight actin-binding proteins from chicken erythrocytes, brain tissue, or intestinal epithelial brush borders. Immunological data and one-dimensional peptide maps of the separated subunits suggest that a common (Mr 240,000) and a variant (Mr 220,000, 235,000, or 260,000) subunit account for the three different heterodimers. These results are in line with the related but distinct morphology of the three proteins observed in micrographs of rotary-shadowed molecules and the finding that the common (Mr 240,000) subunit seems to account for the calcium-dependent calmodulin-binding activity displayed by the three proteins. The possible functions of spectrin-like molecules in nonerythroid cells are discussed.
D000818:Animals; D001923:Brain Chemistry; D002135:Calcium-Binding Proteins; D002147:Calmodulin; D002352:Carrier Proteins / Q000302:isolation & purification; D002645:Chickens; D003429:Cross Reactions; D004910:Erythrocyte Membrane / Q000032:analysis; D007118:Immunoassay; D007422:Intestines / Q000032:analysis; D046911:Macromolecular Substances; D008565:Membrane Proteins / Q000302:isolation & purification; D008840:Microfilament Proteins; D008854:Microscopy, Electron; D008871:Microvilli / Q000032:analysis; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000302:isolation & purification; D010446:Peptide Fragments / Q000032:analysis; D010455:Peptides / Q000302:isolation & purification; D011817:Rabbits; D013049:Spectrin / Q000302:isolation & purification
D002135:Calcium-Binding Proteins; D002147:Calmodulin; D002352:Carrier Proteins; D046911:Macromolecular Substances; D008565:Membrane Proteins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D010446:Peptide Fragments; D010455:Peptides; D013049:Spectrin; C034037:F-actin-binding proteins