Table 1.

Posttranslational modifications of transforming growth factor β (TGF-β) receptors

	Receptors	Sites	Mediators	Other regulators	Functions	References
Phosphorylation	TβRI	GS domain	TβRII		TβRI activation	Wrana et al. 1994; Wieser et al. 1995
		S165	TβRII		Required for TGF-β-mediated apoptosis, but attenuating growth inhibition and extracellular matrix (ECM) production	Souchelnytskyi et al. 1996
		Tyrosine	Unknown		Extracellular signal-regulated kinase (ERK) activation	Lee et al. 2007
	TβRII	S213, S409	Autophosphorylation		TβRII activation	Luo and Lodish 1997
		S416	Autophosphorylation		TβRII inhibition	Luo and Lodish 1997
		Y259, Y336, Y424	Autophosphorylation		TβRII activation	Lawler et al. 1997
Dephosphorylation	TβRI		Protein phosphatase 1	Smad7, SARA, GADD34	Inhibition of TGF-β signaling	Bennett and Alphey 2002; Shi et al. 2004
Ubiquitylation	TβRI		Smurf1/2, WWP1, NEDD4-2	Smad7	Receptor degradation	Kavsak et al. 2000; Ebisawa et al. 2001; Komuro et al. 2004; Kuratomi et al. 2005
	TβRII		Unknown		Receptor degradation	Atfi et al. 2007; Zuo et al. 2013
	BMPRI, BMPRII		Smurf1	Smad7	Receptor degradation	Murakami et al. 2010
	BMPRII		Itch			Durrington et al. 2010
Deubiquitylation	TβRI		UCH37	Smad7	Receptor stabilization	Wicks et al. 2005
			USP4		Receptor stabilization	Zhang et al. 2012
			USP15	TRAF4	Receptor stabilization	Zhang et al. 2013a
			USP11	Smad7?	Receptor stabilization	Al-Salihi et al. 2012
Sumoylation	TβRI	K389	Unknown		Receptor activation	Kang et al. 2008
Neddylation	TβRII	K556, K567	c-Cbl		Receptor stabilization	Zuo et al. 2013

GADD34, Growth arrest and DNA damage protein; SARA, Smad anchor for receptor activation; TRAF4, tumor necrosis factor receptor-associated factor 4; USP, ubiquitin-specific protease.