RESUMO
Lysophospholipids are bioactive lipids and can signal through G-protein-coupled receptors (GPCRs). The best studied lysophospholipids are lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P). The mechanisms of lysophospholipid recognition by an active GPCR, and the activations of lysophospholipid GPCR-G-protein complexes remain unclear. Here we report single-particle cryo-EM structures of human S1P receptor 1 (S1P1) and heterotrimeric Gi complexes formed with bound S1P or the multiple sclerosis (MS) treatment drug Siponimod, as well as human LPA receptor 1 (LPA1) and Gi complexes in the presence of LPA. Our structural and functional data provide insights into how LPA and S1P adopt different conformations to interact with their cognate GPCRs, the selectivity of the homologous lipid GPCRs for S1P versus LPA, and the different activation mechanisms of these GPCRs by LPA and S1P. Our studies also reveal specific optimization strategies to improve the MS-treating S1P1-targeting drugs.
Assuntos
Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/metabolismo , Receptores de Ácidos Lisofosfatídicos/metabolismo , Receptores de Esfingosina-1-Fosfato/metabolismo , Animais , Azetidinas/farmacologia , Azetidinas/uso terapêutico , Compostos de Benzil/farmacologia , Compostos de Benzil/uso terapêutico , Microscopia Crioeletrônica , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/genética , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/isolamento & purificação , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/ultraestrutura , Humanos , Lisofosfolipídeos/metabolismo , Conformação Molecular/efeitos dos fármacos , Simulação de Acoplamento Molecular , Esclerose Múltipla/tratamento farmacológico , Esclerose Múltipla/patologia , Receptores de Ácidos Lisofosfatídicos/genética , Receptores de Ácidos Lisofosfatídicos/isolamento & purificação , Receptores de Ácidos Lisofosfatídicos/ultraestrutura , Proteínas Recombinantes/genética , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/ultraestrutura , Células Sf9 , Imagem Individual de Molécula , Esfingosina/análogos & derivados , Esfingosina/metabolismo , Receptores de Esfingosina-1-Fosfato/genética , Receptores de Esfingosina-1-Fosfato/isolamento & purificação , Receptores de Esfingosina-1-Fosfato/ultraestrutura , SpodopteraRESUMO
Pancreatic ductal adenocarcinoma is one of the most invasive and metastatic cancers and has a dismal 5-year survival rate. We show that N-WASP drives pancreatic cancer metastasis, with roles in both chemotaxis and matrix remodeling. lysophosphatidic acid, a signaling lipid abundant in blood and ascites fluid, is both a mitogen and chemoattractant for cancer cells. Pancreatic cancer cells break lysophosphatidic acid down as they respond to it, setting up a self-generated gradient driving tumor egress. N-WASP-depleted cells do not recognize lysophosphatidic acid gradients, leading to altered RhoA activation, decreased contractility and traction forces, and reduced metastasis. We describe a signaling loop whereby N-WASP and the endocytic adapter SNX18 promote lysophosphatidic acid-induced RhoA-mediated contractility and force generation by controlling lysophosphatidic acid receptor recycling and preventing degradation. This chemotactic loop drives collagen remodeling, tumor invasion, and metastasis and could be an important target against pancreatic cancer spread.
