How do fluticasone propionate and salmeterol each work in Seretide?

In Seretide, inhaled fluticasone propionate at recommended doses has glucocorticoid anti-inflammatory activity in the lungs, reducing asthma symptoms and exacerbations, while salmeterol is a selective long-acting β2-adrenoceptor agonist whose side chain binds the receptor’s exo-site, producing bronchodilation lasting at least 12 hours.