Figure 1.

Btk signaling pathway¹⁵

Btk translocates to the plasma membrane by interacting with phosphatidylinositol-3,4,5 (PIP3) to become membrane-bound, where it undergoes sequential activation through transphosphorylation by Lyn and Syk kinases, followed by autophosphorylation. The downstream substrates of activated Btk and their associated signaling cascades are indicated.