Selective recruitment of src family kinase Hck by leukocyte integrin αMβ2 but not αLβ2 or αXβ2

Integrins are type I heterodimeric (α/β) cell adhesion molecules. They trigger cell-signaling by recruiting cytosolic molecules to their cytoplasmic tails. Integrin α cytoplasmic tail contributes towards integrin function specificity, an important feature of integrins having different α subunits but sharing the same β subunit. Herein, we show that the src family kinase Hck co-capped selectively with leukocyte integrin αMβ2 but not αLβ2 or αXβ2. This was disrupted when the αM cytoplasmic tail was substituted with that of αL or αX. Co-capping was recovered by αL or αX cytoplasmic tail truncation or forced separation of the α and β cytoplasmic tails via salt-bridge disruption.