Gelsolin role in microapocrine secretion

Insect Mol Biol. 2016 Dec;25(6):810-820. doi: 10.1111/imb.12265. Epub 2016 Sep 15.

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.

Keywords: RNA interference; gelsolin; microapocrine secretion; secretory machinery; secretory vesicles.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cloning, Molecular
  • DNA, Complementary / genetics
  • DNA, Complementary / metabolism
  • Gelsolin / genetics*
  • Gelsolin / metabolism
  • Insect Proteins / genetics*
  • Insect Proteins / metabolism
  • Sequence Analysis, DNA
  • Spodoptera / genetics*
  • Spodoptera / metabolism

Substances

  • DNA, Complementary
  • Gelsolin
  • Insect Proteins