Akt phosphorylates Lu and is responsible for JAK2V617F-induced cell adhesion to laminin. (A) Quantification of Lu phosphorylation in the presence or absence (untreated; UT) of PKA (PKAi or H89) or Akt (Akti or LY) inhibitors in HEL-Lu cells. See Figure 2 legend for the quantification method. Typical results of 3 experiments. (B) Effect of the same inhibitors on HEL-Lu cell adhesion to laminin at 2 dyn/cm². Data are normalized to values from the UT HEL-Lu cell adhesion. Paired t test, **P < .01 compared with UT, (n = 3). (C) In vitro phosphorylation of purified recombinant GST, GST-Lu, GST-Lu(v13), and GST-LuS621A by purified Akt. The top (P) and middle (T) panels show the phosphorylation and the total amounts of the proteins, respectively. The P/T ratio indicates the relative phosphorylation level. The bottom panel (P-Akt) shows autophosphorylated Akt as positive control.