Table 1.

Summary of the 10 human PPBD classes

PPBD (class name)	Reported substrate specificitya	Refs.
14-3-3	R-S-X-pS-X-P, R-X-X-X-pS-X-P	(1,20)
BRCT	pS-X-X-F	(21,22)
C2	(Y/F)-(S/A)-(V/I)-pY-(Q/R)-X-(Y/F)-X	(23)
FHA (Forkhead-associated)	pT-X-X-D	(24,25)
MH2 (MAD homology 2)	pS-X-pS	(26)
PBD (Polo-Box domain)	S-(pT/pS)-(P/X)	(27)
PTB (phosphotyrosine binding)	N-P-X-pY, N-P-X-Y	(28)
SH2 (Src homology 2)	pY-X-X-(I/P) (CRK); pY-(I/V/L)-X-(I/V/L) (PTPN11); pY-(M/I/L/V/E)-X-M (PIK3R1)	(29,30)b
WD-40	D-pS-G-Φ-X-pS (BTRC); (I/L/P)-(I/L/P)-pT-P (FBXW7)	(31,32)
WW	(A/P)-P-P-(A/P)-Y; pS-P; pT-P	(33)

^aThe listed information is representative of the vast amount of literature information.

^bThe information also includes our unpublished data on SH2-PPEP microarray data.