TY - JOUR
T1 - Ufd1-Npl4 is a negative regulator of cholera toxin retrotranslocation
AU - McConnell, Elizabeth
AU - Lass, Agnieszka
AU - Wójcik, Cezary
N1 - Funding Information:
We acknowledge the support by internal start-up funds from Indiana University School of Medicine, Evansville.
PY - 2007/4/20
Y1 - 2007/4/20
N2 - The A1 chain of the cholera toxin (CT) undergoes retrotranslocation to the cytosol across the endoplasmic reticulum (ER) membrane by hijacking ER-associated degradation (ERAD). In the cytosol the CT A1 chain stimulates adenylyl cyclase. The VCPUfd1-Npl4 complex mediates retrotranslocation of emerging ER proteins. While one group reported that VCP is required for CT retrotranslocation, another group concluded the opposite. We show that VCP is dispensable for CT retrotranslocation, however RNAi of either Ufd1 or Npl4 induces an increase in adenylyl cyclase activity induced by CT. RNAi of VCP, Ufd1 or Npl4 did not affect adenylyl cyclase activity induced by forskolin. These findings are coherent with our previous report showing that depletion of Ufd1-Npl4 accelerates ERAD of reporter substrates. To integrate contradictory results we propose a new model, where Ufd1-Npl4 is a negative regulator of retrotranslocation, delaying the retrotranslocation of ERAD substrates independently of its association with VCP.
AB - The A1 chain of the cholera toxin (CT) undergoes retrotranslocation to the cytosol across the endoplasmic reticulum (ER) membrane by hijacking ER-associated degradation (ERAD). In the cytosol the CT A1 chain stimulates adenylyl cyclase. The VCPUfd1-Npl4 complex mediates retrotranslocation of emerging ER proteins. While one group reported that VCP is required for CT retrotranslocation, another group concluded the opposite. We show that VCP is dispensable for CT retrotranslocation, however RNAi of either Ufd1 or Npl4 induces an increase in adenylyl cyclase activity induced by CT. RNAi of VCP, Ufd1 or Npl4 did not affect adenylyl cyclase activity induced by forskolin. These findings are coherent with our previous report showing that depletion of Ufd1-Npl4 accelerates ERAD of reporter substrates. To integrate contradictory results we propose a new model, where Ufd1-Npl4 is a negative regulator of retrotranslocation, delaying the retrotranslocation of ERAD substrates independently of its association with VCP.
KW - Adenylyl cyclase
KW - Cholera toxin
KW - ER-associated degradation (ERAD)
KW - Forskolin
KW - Retrotranslocation
KW - Valosin-containing protein (VCP)
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U2 - 10.1016/j.bbrc.2007.02.077
DO - 10.1016/j.bbrc.2007.02.077
M3 - Article
C2 - 17331469
AN - SCOPUS:33847673103
SN - 0006-291X
VL - 355
SP - 1087
EP - 1090
JO - Biochemical and Biophysical Research Communications
JF - Biochemical and Biophysical Research Communications
IS - 4
ER -