Table 3.

Negative regulators of BMP signalling.

Localisation	Types	Classification	Name	Function	Refs.
Extracellular matrix	BMP antagonists	1) The Dan family	Grem1	Prevent BMP signalling by binding BMPs extracellularly	[9–14]
			SOST
			USAG-1
			Dte
			PRDC/Grem2
		2) Noggin	Nog
		3) Chordin	Chrd
		4) Follistatin	FST
		5) Twisted gastrulation	Twsg
Plasma membrane	Nonsignalling BMP pseudoreceptors		BAMBI	Block BMPs through interactions with BMPRIA and BMPRIB	[74]
Cytoplasm	BMPR inhibitor		FKBP12	Suppress BMPRI/ALK2 phosphorylation	[75]
	Inhibitory-Smads		Smad6/7	Repression of the formation and activation of Smads	[21]
	MicroRNAs		MiR-885-3p	Silencing of BMP components	[76]
	Smad-binding protein		Ski and Tob	Directly binds with BMP-specific Smad1/5 and Smad4 and interrupts BMP signalling	[77, 78]
	Ubiquitination and degradation of Smads		Smurf1 and 2	Ubiquitinate and degrade Smad1/5	[79, 80]
Nucleus	Methylation or hypermethylation		Methylated BMPs	Downregulate BMPs via gene methylation or hypermethylation	[81]