Galectin-1 dimers can scaffold Raf-effectors to increase H-ras nanoclustering

A1 Originalartikel i en vetenskaplig tidskrift (referentgranskad)


Interna författare/redaktörer


Publikationens författare: Blazevits O, Mideksa YG, Solman M, Ligabue A, Ariotti N, Nakhaeizadeh H, Fansa EK, Papageorgiou AC, Wittinghofer A, Ahmadian MR, Abankwa D
Förläggare: NATURE PUBLISHING GROUP
Publiceringsår: 2016
Tidskrift: Scientific Reports
Tidskriftsakronym: SCI REP-UK
Volym: 6
Artikelns första sida, sidnummer: 1
Artikelns sista sida, sidnummer: 16
Antal sidor: 16
ISSN: 2045-2322
eISSN: 2045-2322


Abstrakt

Galectin-1 (Gal-1) dimers crosslink carbohydrates on cell surface receptors. Carbohydrate-derived inhibitors have been developed for cancer treatment. Intracellularly, Gal-1 was suggested to interact with the farnesylated C-terminus of Ras thus specifically stabilizing GTP-H-ras nanoscale signalling hubs in the membrane, termed nanoclusters. The latter activity may present an alternative mechanism for how overexpressed Gal-1 stimulates tumourigenesis. Here we revise the current model for the interaction of Gal-1 with H-ras. We show that it indirectly forms a complex with GTP-H-ras via a high-affinity interaction with the Ras binding domain (RBD) of Ras effectors. A computationally generated model of the Gal-1/C-Raf-RBD complex is validated by mutational analysis. Both cellular FRET as well as proximity ligation assay experiments confirm interaction of Gal-1 with Raf proteins in mammalian cells. Consistently, interference with H-rasG12V-effector interactions basically abolishes H-ras nanoclustering. In addition, an intact dimer interface of Gal-1 is required for it to positively regulate H-rasG12V nanoclustering, but negatively K-rasG12V nanoclustering. Our findings suggest stacked dimers of H-ras, Raf and Gal-1 as building blocks of GTP-H-ras-nanocluster at high Gal-1 levels. Based on our results the Gal-1/effector interface represents a potential drug target site in diseases with aberrant Ras signalling.

Senast uppdaterad 2019-08-12 vid 04:03

Dela länk