title: Gelsolin role in microapocrine secretion.
abstract: A role of gelsolin in opening the way along the microvilli for secretory vesicles during microapocrine secretion is proposed here. Data obtained with different techniques showed that many digestive enzymes are released by microapocrine secretion in insects. Proteins that might be involved in the machinery of microapocrine secretion were selected from our transcriptomes and literature searches. The proteins were annexin, Complex actin-related proteins 2 and 3 (ARP 2/3) cofilin, fimbrin, gelsolin 1, gelsolin 2, moesin, myosin 1, myosin 6, protein disulphide isomerase 1 (PDI 1), PDI 2 and profilin. The cDNAs coding for annexin, fimbrin, gelsolin 1, myosin 1, PDI 1 and PDI 2 were cloned and their sequences deposited in GenBank. Only gelsolin 1 and myosin 1 are expressed exclusively in the midgut (semiquantitative reverse transcriptase PCR). As myosin 1 may have a structural role in microvilli, gelsolin 1 is the best guess to be involved in the secretory machinery. A truncated recombinant gelsolin 1 was used to generate antibodies with which it was shown labelling inside and around midgut cell microvilli shown in an electron microscope, reinforcing a microvillar role for gelsolin 1. Suppression of gelsolin 1 synthesis by RNA interference prevents secretory vesicles from advancing inside the microvilli, in agreement with its putative role in severing the actin filaments to free the way for the vesicles.
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: W
authors.initials: W
authors.lastname: Silva
authors.affiliation: Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: A F
authors.initials: AF
authors.lastname: Ribeiro
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: M C P
authors.initials: MC
authors.lastname: Silva
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: W R
authors.initials: WR
authors.lastname: Terra
authors.affiliation: Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, São Paulo, Brazil.
authors.forename: C
authors.initials: C
authors.lastname: Ferreira
mesh_terms: D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics / Q000378:metabolism; D018260:Gelsolin / Q000235:genetics* / Q000378:metabolism; D019476:Insect Proteins / Q000235:genetics* / Q000378:metabolism; D017422:Sequence Analysis, DNA; D018411:Spodoptera / Q000235:genetics* / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D018260:Gelsolin; D019476:Insect Proteins
keywords: RNA interference; gelsolin; microapocrine secretion; secretory machinery; secretory vesicles