Role of p97 and syntaxin 5 in the assembly of transitional endoplasmic reticulum.
Transitional endoplasmic reticulum (tER) consists of confluent rough and smooth endoplasmic reticulum (ER) domains. In a cell-free incubation system, low-density microsomes (1.17 g cc(-1)) isolated from rat liver homogenates reconstitute tER by Mg(2+)GTP- and Mg(2+)ATP-hydrolysis-dependent membrane fusion. The ATPases associated with different cellular activities protein p97 has been identified as the relevant ATPase. The ATP depletion by hexokinase or treatment with either N-ethylmaleimide or anti-p97 prevented assembly of the smooth ER domain of tER. High-salt washing of low-density microsomes inhibited assembly of the smooth ER domain of tER, whereas the readdition of purified p97 with associated p47 promoted reconstitution. The t-SNARE syntaxin 5 was observed within the smooth ER domain of tER, and antisyntaxin 5 abrogated formation of this same membrane compartment. Thus, p97 and syntaxin 5 regulate assembly of the smooth ER domain of tER and hence one of the earliest membrane differentiated components of the secretory pathway.
Roy
L
L
Département de Pathologie et Biologie Cellulaire, Faculté de Médecine, Université de Montréal, Québec, Canada.
Bergeron
J J
JJ
Lavoie
C
C
Hendriks
R
R
Gushue
J
J
Fazel
A
A
Pelletier
A
A
Morré
D J
DJ
Subramaniam
V N
VN
Hong
W
W
Paiement
J
J
D000251:Adenosine Triphosphatases / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D000255:Adenosine Triphosphate / Q000737:chemistry; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D002474:Cell-Free System / Q000378:metabolism; D018870:Endoplasmic Reticulum, Rough / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D018871:Endoplasmic Reticulum, Smooth / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005033:Ethylmaleimide / Q000494:pharmacology; D006160:Guanosine Triphosphate / Q000737:chemistry; D006593:Hexokinase / Q000378:metabolism; D007425:Intracellular Membranes / Q000648:ultrastructure; D008561:Membrane Fusion; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008862:Microsomes, Liver / Q000378:metabolism / Q000648:ultrastructure; D009687:Nuclear Proteins / Q000276:immunology / Q000378:metabolism / Q000502:physiology*; D050765:Qa-SNARE Proteins; D051381:Rats
D000906:Antibodies; D004791:Enzyme Inhibitors; D008565:Membrane Proteins; D009687:Nuclear Proteins; D050765:Qa-SNARE Proteins; D006160:Guanosine Triphosphate; D000255:Adenosine Triphosphate; D006593:Hexokinase; D000251:Adenosine Triphosphatases; C404942:p97 ATPase; D005033:Ethylmaleimide