ROLE OF N-MYRISTYLATION IN TARGETING OF BAND-4.2 (PALLIDIN) IN NONERYTHROID CELLS

Band 4.2 (pallidin) is a major erythrocyte membrane protein which has been detected in a number of nonerythroid cell types. Increasing evide nce suggests that band 4.2 is involved in maintaining membrane stabili ty in the erythrocyte. For example, band 4.2 binds to the integral mem brane protein band 3 and to cytoskeletal proteins in the erythrocyte m embrane, and band 4.2 deficiency results in varying degrees of hemolyt ic anemia. We have previously shown that human erythrocyte band 4.2 is myristylated at its penultimate glycine. Here we report that when exp ressed in both Sf9 and COS cells, myristylated forms of band 4.2 are d etected at different intracellular locations than nonmyristylated form s. We also show that the unspliced form of human erythrocyte band 4.2 (a minor form in reticulocytes which contains an additional 30 amino a cids after the first three N-terminal amino acids compared to the majo r erythroid form) is myristylated only at a barely detectable level, w hile mouse erythrocyte band 4.2 (homologous to the major erythroid for m of human band 4.2) is myristylated at a level comparable to that of human band 4.2. These results suggest that myristylation plays a key r ole in the targeting of band 4.2 to specific intracellular locations a nd is likely to have a role in the function of this protein. (C) 1996 Academic Press, Inc.