Role of syntaxin 18 in the organization of endoplasmic reticulum subdomains.
The presence of subdomains in the endoplasmic reticulum (ER) enables this organelle to perform a variety of functions, yet the mechanisms underlying their organization are poorly understood. In the present study, we show that syntaxin 18, a SNAP (soluble NSF attachment protein) receptor localized in the ER, is important for the organization of two ER subdomains, smooth/rough ER membranes and ER exit sites. Knockdown of syntaxin 18 caused a global change in ER membrane architecture, leading to the segregation of the smooth and rough ER. Furthermore, the organization of ER exit sites was markedly changed concomitantly with dispersion of the ER-Golgi intermediate compartment and the Golgi complex. These morphological changes in the ER were substantially recovered by treatment of syntaxin-18-depleted cells with brefeldin A, a reagent that stimulates retrograde membrane flow to the ER. These results suggest that syntaxin 18 has an important role in ER subdomain organization by mediating the fusion of retrograde membrane carriers with the ER membrane.
Iinuma
Takayuki
T
School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo 192-0392, Japan.
Aoki
Takehiro
T
Arasaki
Kohei
K
Hirose
Hidenori
H
Yamamoto
Akitsugu
A
Samata
Rie
R
Hauri
Hans-Peter
HP
Arimitsu
Nagisa
N
Tagaya
Mitsuo
M
Tani
Katsuko
K
D020126:Brefeldin A / Q000494:pharmacology; D020755:Coat Protein Complex I / Q000378:metabolism; D018870:Endoplasmic Reticulum, Rough / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D018871:Endoplasmic Reticulum, Smooth / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D006367:HeLa Cells; D006801:Humans; D037241:Mannose-Binding Lectins / Q000378:metabolism; D008561:Membrane Fusion; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism; D021381:Protein Transport; D050765:Qa-SNARE Proteins / Q000235:genetics / Q000378:metabolism*; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D014162:Transfection; D014759:Viral Envelope Proteins / Q000378:metabolism
D020755:Coat Protein Complex I; C028391:G protein, vesicular stomatitis virus; C084004:LMAN1 protein, human; D037241:Mannose-Binding Lectins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D050765:Qa-SNARE Proteins; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; D014759:Viral Envelope Proteins; D020126:Brefeldin A