Premium
An antisense oligodeoxynucleotide targeted to chromaffin cell scinderin gene decreased scinderin levels and inhibited depolarization‐induced cortical F‐actin disassembly and exocytosis
Author(s) -
Lejen Tatiana,
Skolnik Kathy,
Rosé Sergio D.,
Marcu Monica G.,
Elzagallaai Abdelbaset,
Trifaró JoséMaría
Publication year - 2001
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1046/j.1471-4159.2001.00024.x
Subject(s) - exocytosis , depolarization , biology , microbiology and biotechnology , chromaffin cell , secretion , munc 18 , synaptic vesicle , adrenal medulla , vesicle , biophysics , biochemistry , endocrinology , catecholamine , membrane
Chromaffin cell secretion requires cortical F‐actin disassembly and it has been suggested that scinderin, a Ca 2+ ‐dependent F‐actin severing protein, controls cortical actin dynamics. An antisense oligodeoxynucleotide targeting the scinderin gene was used to decrease the expression of the protein and access its role in secretion. Treatment with 2 µ m scinderin antisense oligodeoxynucleotide for 4 days produced a significant decrease in scinderin expression and its mRNA levels. The expression of gelsolin, another F‐actin severing protein, was not affected. Scinderin decrease was accompanied by concomitant and parallel decreases in depolarization‐evoked cortical F‐actin disassembly and exocytosis. Similar treatment with a mismatched oligodeoxynucleotide produced no effects. Scinderin antisense oligodeoxynucleotide treatment was also a very effective inhibitor of exocytosis in digitonin‐permeabilized cells stimulated with increasing concentrations of Ca 2+ . This ruled out scinderin antisense interference with stimulation‐induced depolarization or Ca 2+ channel activation. Scinderin antisense treatment decreased the maximum ( B max ) secretory response to Ca 2+ without modifying the affinity ( K m ) of the cation for the exocytotic machinery. Moreover, the antisense treatment did not affect norepinephrine uptake or the expression of dopamine β‐hydroxylase, suggesting that the number and function of chromaffin vesicles was not modified. In addition, scinderin antisense treatment did not alter the expression of proteins involved in vesicle–plasma membrane fusion, such as synaptophysin, synaptotagmin or syntaxin, indicating a lack of effects on the fusion machinery components. These observations strongly suggest that scinderin is a key player in the events involved in the secretory process.