Ski-interacting protein, a bifunctional nuclear receptor coregulator that interacts with N-CoR/SMRT and p300.
Ski-interacting protein (SKIP), a vitamin D receptor (VDR) coactivator, also functions as a repressor in Notch signalling in association with the corepressor SMRT. Here we show that SKIP bifunctionally modulates (activates or represses) Retinoid-X receptor (RXR)- and VDR-dependent gene transcription in a cell line-specific manner, with activation in CV-1 and repression in P19 cells. The coactivator function of SKIP in these cells appeared to correlate with the relative level and ratio of expression of N-CoR and p300, with greater SKIP activation in higher p300-expressing and lower N-CoR-expressing cell-lines. C-terminal deletion of SKIP (delta334-536 aa) was associated with strong activation in both CV-1 and P19 cells. The corepressors N-CoR and SMRT and the coregulator p300 interacted with SKIP through the same N-terminal region (1-200 aa). Overall these results suggest that transcriptional action of SKIP may depend on distinct functional domains and cell line-specific interactions with both corepressors and coactivators.
Leong
Gary M
GM
Bone and Mineral Research Program, Garvan Institute of Medical Research, Sydney, NSW, Australia. g.leong@garvan.org.au
Subramaniam
Nanthakumar
N
Issa
Laura L
LL
Barry
Janelle B
JB
Kino
Tomoshige
T
Driggers
Paul H
PH
Hayman
Michael J
MJ
Eisman
John A
JA
Gardiner
Edith M
EM
D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002460:Cell Line; D002522:Chlorocebus aethiops; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D051548:Histone Acetyltransferases; D051379:Mice; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D056985:Nuclear Receptor Co-Repressor 2; D018167:Receptors, Calcitriol / Q000235:genetics / Q000378:metabolism; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism*; D018168:Receptors, Retinoic Acid / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D047488:Retinoid X Receptors; D017384:Sequence Deletion; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor
D000123:Acetyltransferases; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D051548:Histone Acetyltransferases; D009687:Nuclear Proteins; D056985:Nuclear Receptor Co-Repressor 2; D018167:Receptors, Calcitriol; D018160:Receptors, Cytoplasmic and Nuclear; D018168:Receptors, Retinoic Acid; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; D047488:Retinoid X Receptors; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D000099224:p300-CBP-Associated Factor; C539131:Ncor2 protein, mouse; C491762:Skiip protein, mouse