Table 1.

Membrane binding properties of Akt isoforms and their PH domains determined by SPR analysis.

	Kd (nM) for vesiclesa		Relative affinityb (PI34P2/PIP3)
	PC/PS/PI34P2 (77:20:3)	PC/PS/PIP3 (77:20:3)
Akt1 PHc	310b ± 45	580 ± 80	1.9
Akt2 PHc	220 ± 30	440 ± 50	2.0
Akt3 PHc	340 ± 60	610 ± 65	1.8
Akt1 FLd	960 ± 150	470 ± 70	0.5
Akt2 FLd	410 ± 80	610 ± 100	1.5
Akt3 FLd	900 ± 100	460 ± 90	0.5
Akt1 FLe	880 ± 160	510 ± 210	0.6
Akt2 FLe	360 ± 150	600 ± 200	1.7
Akt3 FLe	940 ± 260	390 ± 120	0.4

^aData represent mean ± S.D. from triplicate equilibrium SPR measurements.

^bK_d for PIP₃ vesicles /K_d for PI34P₂ vesicles.

^cAkt PH domains were expressed as C-terminal EGFP-tagged proteins for enhanced stability. EGFP-tagged Akt PH domains and non-tagged Akt PH domains have essentially the same membrane binding properties.

^dAkt full-length proteins expressed in E. coli.

^eAkt full-length proteins expressed in insect cells.