AN ACTIN-RELATED PROTEIN FROM DICTYOSTELIUM-DISCOIDEUM IS DEVELOPMENTALLY-REGULATED AND ASSOCIATED WITH MITOCHONDRIA

An actin-related protein (ACLA) has been identified in the cellular sl ime mould Dictyostelium discoideum. The complete cDNA sequence indicat es that within the actin superfamily it belongs to the ARP3 family of actin-related proteins together with Arp66B from Drosophila melanogast er, Actin2 from Bos taurus, act2 from Schizosaccharomyces pombe and po ssibly act2 from Caenorhabditis elegans. The ACLA mRNA is regulated du ring development, showing a maximum between 2 and 4 h after starvation . The protein has been expressed in E. coli and antibodies raised agai nst it. Immunofluorescence microscopy shows that ACLA protein co-local ises with mitochondria; the protein copurifies with Dictyostelium mito chondria.