Table 2 Protein-protein interactions involving Id proteins

Id1-4

Class I and II bHLH proteins

Dominant negative regulation of bHLH factors

[61–63, 236]

Id2

pRb and related pocket proteins p107 and p130

Inhibition of pRb-mediated cell-cycle arrest (as no interaction between the pRb small pocket and Id2 was detected by mass spectrometry and NMR spectroscopy [136], a multiprotein complex is likely to be formed)

[64, 65]

Id2

ENH

Id-protein localization in the cytoplasm by association of the Id2 HLH and ENH LIM domains

[66, 67]

Id1-3

p204

Id-protein localization in the cytoplasm

[68, 69]

Id1-3

Ets-domain proteins Elk-1 and SAP-1/-2

Inhibition of the winged-helix-turn-helix transcription factors regulating the expression of immediate-early response genes such as c-Fos and Egr1

[70]

Id1

MIDA1

Inhibition of MIDA1-Z-DNA interaction with stimulation of cell growth and inhibition of neural differentiation

[71, 72, 344, 345]

Id1-3

Pax-2/-5/-8

Inhibition of the paired-box transcription factors involved in development

[73]

Id1, Id2

Adenovirus E1A protein

Induction of apoptosis in cells expressing p53 mutants

[74]

Id2, Id3

ADD1/SREBP-1c

Inhibition of the bHLH-LZ transcription factor that regulates the expression of adipocyte genes

[75]

Id1

C8, HBX

Induction of proteasome-mediated HBX degradation

[76]

Id1

S5a

Suppression of the Id-protein activity

[77]

Id1, Id3

CSN5 (Id1, Id3), CSN7 (Id3)

Suppression of Id-protein ubiquitination by CSN-mediated phosphorylation

[78]

Id1-3

USP1

Id-protein deubiquitination

[79]

Id2

Apc/C subunits Apc1, Apc5, Apc8/Cdc23

Id2-protein degradation

[50]

Id1

Caveolin-1

Induction of cell migration and chemotherapy resistance in prostate cancer

[80]

Id1-4

FHL2

Antagonism of the inhibitory effect of the Id proteins on E47-mediated transcription

[81]

Id2

VHL-elongin-C

Inhibition of ubiquitination and degradation of HIF2α

[82]

Id1

ERβ1

Inhibition of cell proliferation and p21 up-regulation

[83]