title: Actin-related proteins in Anabaena spp. and Escherichia coli.
abstract: Actin has been described in all eukaryotic cells as the major microfilament cytoskeletal protein. Although prokaryotic cells do not have a cytoskeleton, proteins related to the latter have been found in different prokaryotic species. We have found prokaryotic actin-related proteins in the enterobacterium Escherichia coli and in the cyanobacteria Anabaena cylindrica and Anabaena variabilis. They were identified by the following criteria: (1) by cross-reaction with a fluorescent conjugated anti-actin (rat-brain) mAb by Western blot analysis (in total cellular extracts); (2) specific binding of acetone powder and soluble cellular extracts to DNase I; and (3) specific binding of cells and total cellular extracts to phalloidin. In E coli, specific binding of phalloidin labelled with rhodamine to cells was detected by spectrofluorometry. In total cellular extracts, three bands of 60, 43 and 35 kDa were weakly recognized by the mAb by Western blot analysis; this recognition increased when phalloidin was added to the extracts. Furthermore, three polypeptides of kDa were isolated by binding to DNase I, showing pI values of 6.7, 6.65 and 6.6, less acidic than all reported actin pI values. In A. cylindrica and A. variabilis, specific binding of phalloidin labelled with rhodamine to cells was also detected by spectrofluorometry. In total and soluble cellular extracts, the mAb recognized two bands of 45 and 40 kDa by Western blot analysis, but only the first was purified by binding to DNase I, and it showed three isoforms of pI values 6.8, 6.5 and 6.4. These results suggest the presence, in prokaryotes, of proteins with similar biochemical characteristics to eukaryotic actin.
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: Alma L
authors.initials: AL
authors.lastname: Guerrero-Barrera
authors.affiliation: División de Investigación Básica, Instituto Nacional de Cancerología, San Fernando No. 22, Tlalpan DF 14000, Mexico.|Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: Claudia M
authors.initials: CM
authors.lastname: García-Cuéllar
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: José D
authors.initials: JD
authors.lastname: Villalba
authors.affiliation: Departamento de Ingeniería Genética, Centro de Investigación y de Estudios Avanzados del IPN, Km 9.6, Libramiento Norte, Carretera Irapuato-León, Irapuato, Gto, Mexico.
authors.forename: Magdalena
authors.initials: M
authors.lastname: Segura-Nieto
authors.affiliation: Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: Carlos
authors.initials: C
authors.lastname: Gómez-Lojero
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: Magda E
authors.initials: ME
authors.lastname: Reyes
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: José M
authors.initials: JM
authors.lastname: Hernández
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Garcia
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 14-740, México, DF 07000, Mexico.
authors.forename: Mireya
authors.initials: M
authors.lastname: de la Garza
mesh_terms: D000199:Actins / Q000737:chemistry* / Q000276:immunology; D017033:Anabaena / Q000737:chemistry* / Q000276:immunology / Q000648:ultrastructure; D000818:Animals; D000907:Antibodies, Bacterial / Q000276:immunology; D001426:Bacterial Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D001704:Biopolymers; D015153:Blotting, Western; D003429:Cross Reactions; D003850:Deoxyribonuclease I / Q000378:metabolism; D004926:Escherichia coli / Q000737:chemistry* / Q000276:immunology / Q000648:ultrastructure; D019143:Evolution, Molecular; D010590:Phalloidine / Q000378:metabolism; D010940:Plant Proteins / Q000737:chemistry / Q000276:immunology / Q000302:isolation & purification*; D011485:Protein Binding; D051381:Rats; D013045:Species Specificity
chemical_list: D000199:Actins; D000907:Antibodies, Bacterial; D001426:Bacterial Proteins; D001704:Biopolymers; D010940:Plant Proteins; D010590:Phalloidine; D003850:Deoxyribonuclease I