Purification and structural studies of rabbit erythrocyte cytochrome b5

Schafer, Dorothy A.; Hultquist, Donald E.

doi:10.1016/s0006-291x(83)80006-0

Cited by 10 publications

References 14 publications

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NADH-Cytochrome b5 Reductase and Cytochrome b5 the Problem of Posttranslational Targeting to the Endoplasmic Reticulum

Borgese

D’Arrigo

Silvestris

et al. 1993

Subcellular Biochemistry

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Cytochrome b5 and NADH-cytochrome b, reductase are integral membrane proteins with cytosolic active domains and short membrane anchors, which are inserted post-translationally into their target membranes. Both are produced as different isoforms, with different localizations, in mammalian cells. In the rat, the reductase gene generates two transcripts by an alternative promoter mechanism: a ubiquitous mRNA coding for the myristylated membrane-bound form, and an erythroid mRNA which generates both the soluble form and a nonmyristylated membrane-binding form. The available evidence indicates that the ubiquitous myristylated form binds to the cytosolic face of both outer mitochondrial membranes and ER. In contrast, two genes code for two homologous forms of cytochrome b5, one of which is found on outer mitochondrial membranes, the other on the ER. The gene specifying the ER form probably also generates an erythroid-specific mRNA by alternative splicing, which codes for soluble cytochrome bS. Possible molecular mechanisms responsible for the observed locahzations of these different enzyme isoforms are discussed.Endoplasmic reticulum; Outer mitochondrial membrane; Protein myristylation; Alternative promoter

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