EF-1 alpha is associated with a cytoskeletal network surrounding protein bodies in maize endosperm cells

By using indirect immunofluorescence and confocal microscopy, we documented changes in the distribution of elongation factor-1 alpha (EF-1 alpha), actin, and microtubules during the development of maize endosperm cells. In older interphase cells actively forming starch grains and protein bodies, the protein bodies are enmeshed in EF-1 alpha and actin and are found juxtaposed with a multidirectional array of microtubules. Actin and EF-1 alpha appear to exist in a complex, because we observed that the two are colocalized, and treatment with cytochalasin D resulted in the redistribution of EF-1 alpha. These data suggest that EF-1 alpha and actin are associated in maize endosperm cells and may help to explain the basis of the correlation we found between the concentration of EF-1 alpha and lysine content. The data also support the hypothesis that the cytoskeleton plays a role in storage protein deposition. The distributions of EF-1 alpha, actin, and microtubules change during development. We observed that in young cells before the accumulation of starch and storage protein, EF-1 alpha, actin, and microtubules are found mainly in the cell cortex or in association with nuclei.