Roles for SH2 and SH3 domains in Lyn kinase association with activated FcepsilonRI in RBL mast cells revealed by patterned surface analysis.
In mast cells, antigen-mediated cross-linking of IgE bound to its high-affinity surface receptor, FcepsilonRI, initiates a signaling cascade that culminates in degranulation and release of allergic mediators. Antigen-patterned surfaces, in which the antigen is deposited in micron-sized features on a silicon substrate, were used to examine the spatial relationship between clustered IgE-FcepsilonRI complexes and Lyn, the signal-initiating tyrosine kinase. RBL mast cells expressing wild-type Lyn-EGFP showed co-redistribution of this protein with clustered IgE receptors on antigen-patterned surfaces, whereas Lyn-EGFP containing an inhibitory point mutation in its SH2 domain did not significantly accumulate with the patterned antigen, and Lyn-EGFP with an inhibitory point mutation in its SH3 domain exhibited reduced interactions. Our results using antigen-patterned surfaces and quantitative cross-correlation image analysis reveal that both the SH2 and SH3 domains contribute to interactions between Lyn kinase and cross-linked IgE receptors in stimulated mast cells.
Department of Chemistry and Chemical Biology, Cornell University, Ithaca, NY 14853-1301, USA.
Stephanie
S
Hammond
Alice
A
Wagenknecht-Wiesner
Sarah L
SL
Veatch
David
D
Holowka
Barbara
B
Baird
D000818:Animals; D008407:Mast Cells / Q000378:metabolism*; D051379:Mice; D017354:Point Mutation / Q000235:genetics / Q000502:physiology; D011485:Protein Binding; D017455:Receptors, IgE / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018909:src Homology Domains / Q000235:genetics / Q000502:physiology*; D019061:src-Family Kinases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*
D017455:Receptors, IgE; C060902:lyn protein-tyrosine kinase; D019061:src-Family Kinases