P2 integrins

Integrins are heterodimeric (aP) complexes expressed on leucocytes. Monocytes and lymphocytes express pi integrins and all leucocytes express integrins having a common P2 chain but different a chains. Integrins are involved in cell-matrix as well as cell-cell interactions. The synthesis of P1 and P2 integrins is stimulated by endothelium-derived leucocyte chemoattractants such as monocyte chemoattractant protein-1 (MCP-1). The endothelium ICAM-1 is subject to upregulation by leucocyte-derived cytokines. 

The selectins are a family of lectins that mediate the movement of leukocytes from the bloodstream into sites of inflammation. This multistep cascade proceeds by initial attachment leading to the rolling of leukoc)rtes along endothelial vasculature via selectin-carbohydrate interactions. Subsequent firm adhesion requires chemoattractant activation of leukocyte p2 integrins which mediate arrest through interaction with endothelial receptors. Leukocytes then extravasate between endothelial cells in the direction of chemoattractants as indicated in O Fig. 3 [42]. 

Fig. 21. Unique structures of the N-glycans of P2 integrins. Data from Asada et al. [417]. R = OlcNAcPI-4GlcNAc.

Bunting, M., Harris, E.S., McIntyre, T.M., Prescott, S.M. and Zimmerman, G.A. (2002). Leukocyte adhesion deficiency syndromes adhesion and tethering defects involving P2 integrins and selectin ligands. Curr. Opin. Hematol. 9, 30-35. 

Hellewell, PC., Young, S.K., Henson, PM. and Worthen, G.S. (1994). Disparate role of the p2-integrin CD18 in the local accumulation of neutrophils in pulmonary and cutaneous inflammation in the rabbit. Am. J. Respir. Cell Mol. Biol. 10, 391-398. 

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