LAT is a scaffold protein associated with the membrane. It itself does not have any catalytic activity but it provides binding sites for signalling molecules via phosphorylated tyrosine residues. LAT associates with another scaffolding protein Slp-76 via the Grap2 adaptor protein, which provides additional binding sites. Together LAT and Slp-76 provide a platform for the recruitment of many downstream signalling molecules. By bringing these signalling molecules into close proximity, they can then be activated by Lck, Zap70 and others kinases. Therefore, the LAT/Slp76 complex act as a highly cooperative signalosome.