Warning: file_get_contents(https://eutils.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&id=16796817
&cmd=llinks): Failed to open stream: HTTP request failed! HTTP/1.1 429 Too Many Requests
in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 215
Warning: imagejpeg(C:\Inetpub\vhosts\kidney.de\httpdocs\phplern\16796817
.jpg): Failed to open stream: No such file or directory in C:\Inetpub\vhosts\kidney.de\httpdocs\pget.php on line 117 J+Cell+Mol+Med
2006 ; 10
(2
): 519-28
Nephropedia Template TP
gab.com Text
Twit Text FOAVip
Twit Text #
English Wikipedia
Caveolar nanospaces in smooth muscle cells
#MMPMID16796817
Gherghiceanu M
; Popescu LM
J Cell Mol Med
2006[Apr]; 10
(2
): 519-28
PMID16796817
show ga
Caveolae, specialized membrane nanodomains, have a key role in signaling
processes, including calcium handling in smooth muscle cells (SMC). We explored
the three-dimensional (3D) architecture of peripheral cytoplasmic space at the
nanoscale level and the close spatial relationships between caveolae,
sarcoplasmic reticulum (SR), and mitochondria, as ultrastructural basis for
excitation-contraction coupling system and, eventually, for
excitation-transcription coupling. About 150 electron micrographs of SMC showed
that superficial SR and peripheral mitochondria are rigorously located along the
caveolar domains of plasma membrane, alternating with plasmalemmal dense plaques.
Electron micrographs made on serial ultrathin sections were digitized, then
computer-assisted organellar profiles were traced on images, and automatic 3D
reconstruction was obtained using the Reconstruct software. The reconstruction
was made for 1 microm(3) in rat stomach (muscularis mucosa) and 10 microm(3) in
rat urinary bladder (detrusor). Caveolae, peripheral SR, and mitochondria close
appositions create coherent cytoplasmic nanoscale subdomains of about 15 nm
distance. Apparently, 80% of caveolae establish close contacts with SR and about
10% establish close contacts with mitochondria in both types of SMC. Thus, our
results showed that caveolae and peripheral SR build Ca(2+) release units at
which mitochondria often could play a part. The couplings caveolae-SR occupy
4.19% of cellular volume in stomach and 3.10% in rat urinary bladder, while
couplings caveolae-mitochondria occupy 3.66% and 3.17% respectively. We conclude
that there are strategic caveolae-SR or caveolae-mitochondria contacts at the
nanoscale level in the cortical cytoplasm of SMC, presumably responsible for
vectorial control of free Ca(2+) cytoplasmic concentrations in definite
nanospaces. This may account for selective activation of specific Ca(2+)
signaling pathways.
free
free
free
