Actin‐binding proteins are conserved from slime molds to man

Abstract

DNA clones encoding the actin‐binding proteins α‐actinin and severin from Dictyostelium discoideum were isolated and sequenced. Comparisons of the deduced amino acid sequences with proteins from other species showed striking similarities at distinct regions. The F‐actin cross‐linking molecule α‐actinin carries two characteristic EF‐hand structures highly homologous to the Ca²⁺‐binding loops of proteins from the calmodulin superfamily. An N‐terminal region that is conserved in α‐actinin from D. discoideum and vertebrates is also related to parts of the dystrophin sequence and might represent the F‐actin binding site. Severin, gelsolin, villin, and fragmin share homologous sequences that are believed to participate in the severing activity of these proteins.