INVESTIGADORES
SESMA Juliana Ines
artículos
Título:
Vesicular nucleotide transporter regulates the nucleotide content in airway epithelial mucin granules
Autor/es:
JULIANA I. SESMA; SILVIA M. KREDA; SEIKO F. OKADA; CATHARINA VAN HEUSDEN; LAMA MOUSSA; LISA C. JONES; WANDA O'NEAL; NATSUKO TOGAWA; MIKI HIASA; YOSHINORI MORIYAMA; EDUARDO R. LAZAROWSKI
Revista:
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY
Editorial:
AMER PHYSIOLOGICAL SOC
Referencias:
Lugar: Bethesda; Año: 2013 vol. 304 p. 976 - 984
ISSN:
0363-6143
Resumen:
Vesicular nucleotide transporter regulates the
nucleotide content in airway epithelial mucin granules. Am J
Physiol Cell Physiol 304: C976?C984, 2013. First published
March 6, 2013; doi:10.1152/ajpcell.00371.2012.?Nucleotides
within the airway surface liquid promote fluid secretion via activation
of airway epithelial purinergic receptors. ATP is stored within and
released from mucin granules as co-cargo with mucins, but the
mechanism by which ATP, and potentially other nucleotides, enter the
lumen of mucin granules is not known. We assessed the contribution
of the recently identified SLC17A9 vesicle nucleotide transporter
(VNUT) to the nucleotide availability within isolated mucin granules
and further examined the involvement of VNUT in mucin granule
secretion-associated nucleotide release. RT-PCR and Western blot
analyses indicated that VNUT is abundantly expressed in airway
epithelial goblet-like Calu-3 cells, migrating as a duplex with apparent
mobility of 55 and 60 kDa. Subcellular fractionation studies indicated
that VNUT55 was associated with high-density mucin granules,
whereas VNUT60 was associated with low-density organelles. Immu-
nofluorescence studies showed that recombinant VNUT localized to
mucin granules and other organelles. Mucin granules isolated from
VNUT short hairpin RNA-expressing cells exhibited a marked reduc-
tion of ATP, ADP, AMP, and UTP levels within granules. Ca2-
regulated vesicular ATP release was markedly reduced in these cells,
but mucin secretion was not affected. These results suggest that
VNUT is the relevant nucleotide transporter responsible for the
uptake of cytosolic nucleotides into mucin granules. By controlling
the entry of nucleotides into mucin granules, VNUT contributes to
the release of purinergic signaling molecules necessary for the
proper hydration of co-released mucins.