Fig. 7. CaM is a putative protein ligand for multiple PH domains.

(A) Calmodulin target prediction for mouse PH domain-containing proteins annotated in Uniprot predicts that >50% of PH domains bind CaM. Predicted relative affinities are based on the number of consecutive amino acids (aa) scoring 8 in the algorithm: low (1–7 consecutive aa), medium (8–14 aa), and high affinity (15–21 aa). See table S3 for the results of the analysis of the 236 PH domains tested (B) PH domains with indicated predicted affinities and the PH domain of Itk were assessed in precipitation assays with apo-CaM and Ca²⁺/CaM (+/− Ca²⁺). For some PH domain-YFP fusions, smaller fragments likely derived from internal translational start sites were observed.