PH domains mainly bind
Pleckstrin-homology (PH) domains bind specific phosphoinositides such as PIP3 or PIP2 with high affinity. Recruitment of PH-domain-containing proteins to membrane regions enriched in these lipids is a key mechanism by which PI3K signaling localizes effectors such as AKT and PDK1. The PH domain therefore functions as a lipid-regulated membrane-targeting module.
Ref: NCERT Biology Class 11–12 Alberts et al Molecular Biology of the Cell Lodish et al, Molecular Cell Biology Cooper & Hausman, The Cell Abbas et al., Cellular and Molecular Immunology (for immunology sections)