Evidence for a membrane skeleton in higher plants A spectrin-like polypeptide co-isolates with rice root plasma membranes

AbstractA fraction enriched in plasma membranes was isolated from rice roots by differential centrifugation and aqueous polymer two-phase partitioning. Analysis of the fraction by SDS-PAGE showed the presence of several low mobility polypeptides (Mr> 100 kDa). One of these polypeptides (Mr ~ 230 kDa) was specifically recognized by polyclonal antibodies to human erythrocyte spectrin. This finding suggests that a higher plant spectrin-based membrane skeleton may be preserved and studied using high-purity plasma membrane fractions obtained by aqueous polymer two-phase partitioning