Premium
Tyrosine 785 is a major determinant of Trk‐‐substrate interaction.
Author(s) -
Obermeier A.,
Halfter H.,
Wiesmüller K.H.,
Jung G.,
Schlessinger J.,
Ullrich A.
Publication year - 1993
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1993.tb05734.x
Subject(s) - biology , tyrosine , substrate (aquarium) , substrate specificity , trk receptor , microbiology and biotechnology , biochemistry , receptor , enzyme , ecology , neurotrophin
Interaction of the nerve growth factor (NGF) receptor/Trk with cellular substrates was investigated by transient co‐overexpression in human 293 fibroblasts using ET‐R, a chimeric receptor consisting of the epidermal growth factor receptor (EGF‐R) extracellular ligand binding domain and the Trk transmembrane and intracellular signal‐generating sequences. The chimera was fully functional, and associated with and phosphorylated phospholipase C gamma (PLC gamma), ras GTPase‐activating protein (GAP) and the non‐catalytic subunit of phosphatidylinositol‐3′‐kinase, p85, in a ligand‐dependent manner. Deletion of 15 C‐terminal amino acids, including tyrosine 785 (Y‐785) abrogated receptor and substrate phosphorylation activities. Mutation of Y‐785 to phenylalanine somewhat impaired receptor phosphorylation activity, which was reflected in reduced GAP and p85 phosphorylation. In contrast, ET‐YF phosphorylation of PLC gamma was significantly reduced, while the high affinity association potential with this substrate was abrogated by this point mutation in vitro and in intact cells. Furthermore, a tyrosine‐phosphorylated synthetic C‐terminal peptide competitively inhibited Trk cytoplasmic domain association with PLC gamma. Thus, the short C‐terminal tail appears to be a crucial structural element of the Trk cytoplasmic domain, and phosphorylated Y‐785 is a major and selective interaction site for PLC gamma.