Differential requirement of the last C-terminal tail of Met receptor for cell transformation and invasiveness

Abstract

Biological responses to Hepatocyte Growth Factor are mediated by the tyrosine kinase receptor encoded by the Met oncogene. Under physiological conditions, Met triggers a multi-step genetic program called`invasive growth' including cell-dissociation, invasion of extracellular matrices and growth. When constitutively activated, Met can induce cell transformation and metastasis. Phosphorylation of two docking tyrosines in the receptor tail is essential for all biological responses. To investigate the role of the C-terminal part of Met, we have generated mutants lacking either the last 26 or 47 amino acids. As expected, mutants lacking the docking sites fail to mediate cell transformation and invasion. Interestingly, while Met D26 can mediate invasion, its transforming ability is severely impaired. Moreover, the lack of the last 26 amino acids strongly reduces Met ability to phosphorylate substrates in vitro and in vivo. These data indicate that the last 26 amino acids are required to confer the kinase its full enzymatic activity, which is critical for cell transformation but dispensable for invasive properties. Finally, we also show that upregulation of Met enzymatic activity by insertion of a point mutation in the kinase domain (M1250T) overcomes the regulatory role played by the last 26 amino acids of the tail. It is concluded that the C-terminal domain of Met is crucial not only for recruitment of transducers but also for regulation of receptor enzymatic activity. Oncogene (2001) 20, 5493 ± 5502.

RET/Papillary Thyroid Carcinoma Oncogenic Signaling through the Rap1 Small GTPase

“…The pcDNA3 expression vector encoding Gab1 was a kind gift of P. Gual and S. Giordano (Instituto per la Ricerca e la Cura del Cancro, Candiolo, Torino, Italy; ref. 27). The pCMV6-CrkII plasmid was from OriGene Technologies, Inc. (Rockville, MD).…”

Redundant Roles for Met Docking Site Tyrosines and the Gab1 Pleckstrin Homology Domain in InlB-Mediated Entry of Listeria monocytogenes

“…Similarly, these two tyrosines are not absolutely required for Gab1 phosphorylation in mouse hepatocytes expressing physiological levels of Met or in COS-7 cells transiently expressing the Tpr-Met oncoprotein. Mutation of tyrosines 1349 and 1356 reduces, but does not abolish, Gab1 phosphorylation in these two cell lines (13,26). In contrast to the situation in T47D, COS-7 cells, or hepatocytes, in MDCK cells the two tyrosines are essential for Gab1 phosphorylation (42).…”

“…In one previous study examining tyrosines 1349 and 1356 in Met, mutation of these residues to phenylalanine was found to cause a nearly complete defect in Met-dependent Gab1 phosphorylation (42). However, in other reports significant Gab1 phosphorylation was detected in cells expressing Met in which the docking site tyrosines were mutated or deleted (13,26). The reasons for these differences in Gab1 phosphorylation are not understood but may be due to the different cell lines employed.…”

Enhanced Prediction of Src Homology 2 (SH2) Domain Binding Potentials Using a Fluorescence Polarization-derived c-Met, c-Kit, ErbB, and Androgen Receptor Interactome

“…We observed that Tyr(P)-1349 was able to recruit primarily SH2 domains from PLCG1 and SH2D1B with moderate affinity. c-Met Tyr(P)-1365 has been shown to be important for full enzymatic activity of the receptor and has been suggested to recruit downstream signaling mediators (40). We identified interactions with SH2 domains from several c-Src family kinases, tensin family, PLCG1, RASA1, SH2D1A, and SH2D1B proteins (Fig.…”