Table 1.

E3 ubiquitin ligases implicated in transforming growth factor-β (TGF-β) signaling

Target proteins	E3 ubiquitin ligase	Adaptor	Reference
TβRI	Smurf1	Smad7	Ebisawa et al. (2001)
	Smurf1	Smad6/7	Murakami et al. (2003)
	Smurf1	Smad7 & FKBP12	Yamaguchi et al. (2006)
	Smurf2	Smad7	Kavsak et al. (2000)
	NEDD4-2	Smad7	Kuratomi et al. (2005)
	WWP1/Tiul1	Smad7	Komuro et al. (2004) and Seo et al. (2004)
Smad1/5/8	Smurf1		Zhu et al. (1999)
Smad1/5	Smurf1		Shi et al. (2004)
	Smurf1	LMP-1	Sangadala et al. (2006)
	Smurf1	Smad6/7	Murakami et al. (2003)
Smad1	Smurf2		Zhang et al. (2001)
	CHIP		Li et al. (2004, 2005)
Smad5	Smurf1		Ying et al. (2003)
Smad2	Smurf2		Lo & Massague (1999), Lin et al. (2000) and Zhang et al. (2001)
	Nedd4-2		Kuratomi et al. (2005)
	WWP1/Tiul1	TGIF	Seo et al. (2004)
	Itch/AIP4		Bai et al. (2004)
	Cbl-b		Wohlfert et al. (2006)
Smad3	CHIP		Xin et al. (2005)
	ROC1–SCF–β-TrCP1		Fukuchi et al. (2001)
	PRAJA		Saha et al. (2006)
Smad4	Smurf1	Smad2/6/7	Moren et al. (2005)
	Smurf2	Smad2/6/7	Moren et al. (2005)
	NEDD4-2	Smad7	Moren et al. (2005)
	WWP1	Smad7	Moren et al. (2005)
	CHIP		Li et al. (2004)
	SCF–Skp2		Liang et al. (2004)
	SCF–β-TrCP1		Wan et al. (2004, 2005)
	Ecto		Dupont et al. (2005)
Smad6/7	Smurf1		Murakami et al. (2003)
Smad7	Smurf1		Ebisawa et al. (2001)
	Smurf2		Kavsak et al. (2000)
	Arkadia	Axin	Liu et al. (2006)
	Arkadia		Koinuma et al. (2003)
ELF	PRAJA		Saha et al. (2006)
SnoN	Smurf2	Smad2	Bonni et al. (2001)
	APC	Smad3>Smad2	Stroschein et al. (2001)
	APC–CDH1	Smad3	Wan et al. (2001)
HEF1	Itch/AIP4	Smad3	Feng et al. (2004)
	APC–CDH1	Smad3	Liu et al. (2000) and Nourry et al. (2004)
Runx2	Smurf1	Smad6	Shen et al. (2006)