| Previously , we identified Src homology 2 B ( SH 2 B ) and APS , which are structurally similar adapter proteins , as substrates of Trk kinases . ^^^ In the present study , we demonstrate that both SH 2 B and APS exist in cells as homopentamers and / or heteropentamers , independent of Trk receptor activation . ^^^ Together , these results indicate that the multimeric adapters SH 2 B and APS influence neurotrophin signaling through direct modulation of Trk receptor autophosphorylation . . ^^^ SH 2 B and APS are multimeric adapters that augment TrkA signaling . ^^^ |