Table 1.

Prediction of putative casein kinase 2 (CK2) phosphorylation sites in AtSIG6

									Position in consensus motif
Position	Aminoacid	NetPhos 2.0	NetPhosK 1.0	KinasePhos 2.0	disphos	gps	PREDPhospho	ScanSite	−2	−1	*	+1	+2	+3	+4	Homology
26	Serine	*				*			Y	S	S	P	S	S	V
94	Serine	*	*	*	*	*	*		L	V	S	S	R	E	D
95	Serine	*	*	*	*	*		*	V	S	S	R	E	D	E
149	Serine	*							A	L	S	A	S	K	Q
174	Serine	*		*	*	*			S	L	S	T	S	S	S	AtSIG2
176	Serine	*			*			*	S	T	S	S	S	M	S
180	Serine	*			*	*	*	*	S	M	S	L	P	E	K	AtSIG5
206	Serine		*						P	K	S	N	D	V	D
244	Threonine			*					P	E	T	K	Q	L	L
249	Threonine		*						L	L	T	A	K	E	E	AtSIG1-5
282	Threonine		*						E	P	T	I	G	E	W
306	Serine	*		*					G	R	S	S	R	E	K
411	Serine	*		*		*			R	P	S	K	E	E	L	AtSIG4, 5
423	Threonine			*					V	S	T	E	K	L	D
445	Serine			*		*			I	W	S	D	Q	D	T
450	Threonine		*			*			D	T	T	F	Q	E	I	AtSIG4
458	Serine	*	*	*		*			P	D	S	G	I	E	T	AtSIG1, 3, 5
462	Threonine			*					I	E	T	P	T	M	S	AtSIG2, 3, 4
484	Serine	*		*		*			V	L	S	P	K	E	R	AtSIG4
504	Serine	*	*			*			Q	R	S	L	S	E	I	AtSIG1-5
CK2 consensus substrate site											S/T	x	x	E/D	x

Prediction tools NetPhos 2.0 (Blom et al., 1999), NetPhosK 1.0 (Blom et al., 2004), KinasePhos 2.0 (Wong et al., 2007), disphos (Diella et al., 2004), gps (Xue et al., 2005), PREDPhospho (Kim et al., 2004) and ScanSite (Obenauer et al., 2003) were used, leading to the detection of putative sites (+). Those selected for subsequent experiments are set in bold. The phosphoacceptor residue (*) and the acidic residue at the n + 3 position are marked in bold. Arabidopsis sigma factors showing regional similarity with AtSIG6 CK2 sites are indicated in the last column (Figure S2 for detailed positions). Bottom: consensus sequence of CK2 phosphorylation sites (Meggio and Pinna, 2003).