Inferred from mouse: GRB2 associated binding protein 2 (GAB2) is believed to bind and be phosphorylated in response to Interleukin-2 (IL2) and Interleukin-15 (IL15) stimulation. Its phosphorylation is greatly diminished by mutation of the site in the Interleukin-2 Receptor beta chain (Y338F) (IL2RB, IL2Rβ) that recruits SHC transforming protein 1 (SHC1) (Gadina et al.2000, Wöhrle et al.2009, Gesbert et al. 1998, Brockdorff et al. 2001). GAB2 is a phosphoprotein that is suggested to associates with PI3kinase, Growth factor receptor-bound protein 2 (GRB2) and Tyrosine protein phosphatase non-receptor type 11 (PTPN11 or SHP2) in T and Natural Killer (NK) cells (Gu et al. 2000).This is a black box event because GAB2 binding is inferred from IL15 stimulation of GAB2 phosphorylation (Brockdorff et al. 2001). More in detail, human and mouse IL15 have 70.2% amino acid sequence similarity and exhibit similar trans-presentation mechanism, signal transduction machinery and biological activities. Similarly, human IL15 shows cross-reactivity with mouse cells and it was demonstrated that human and mouse IL15 showed similar responses in mouse models (Stoklasek et al. 2006) (Patidar et al. data not published).