A shortcut from GPCR signaling to Rac-mediated actin cytoskeleton through an ELMO/DOCK complex

PI3King the right partner: unique interactions and signaling by p110β

Phosphoinositide 3-kinases (PI3Ks) are central regulators of cellular responses to extracellular stimuli, and are involved in growth, proliferation, migration, and metabolism. The Class I PI3Ks are activated by Receptor Tyrosine Kinases (RTKs) or G Protein-Coupled Receptors (GPCRs), and their signaling is commonly deregulated in disease conditions. Among the class I PI3Ks, the p110β isoform is unique in being activated by both RTKs and GPCRs, and its ability to bind Rho-GTPases and Rab5. Recent studies have characterized these p110β interacting partners, defining the binding mechanisms and regulation, and thus provide insight into the function of this kinase in physiology and disease. This review summarizes the developments in p110β research, focusing on the interacting partners and their role in p110β-mediated signaling.

ELMO3 is a novel biomarker for diagnosis and prognosis of non-small cell lung cancer

BACKGROUND

To investigated the diagnostic and prognostic value of engulfment and cell motility (ELMO3) in non small cell lung cancer (NSCLC).

METHODS

The expression of ELMO3 at mRNA levels were detected using reverse transcription quantitative real-time polymerase chain reaction (qRT-PCR) in 125 NSCLC patients' tissues and adjacent tissues, as well as in the serum of 125 NSCLC patients and 89 healthy controls. Then, receiver operating characteristic curve (ROC), Kaplan-Meier and Cox regression analysis were adopted to estimate the potential diagnostic and prognostic value of ELMO3, respectively.

RESULTS

ELMO3 expression level was significantly up-regulated in NSCLC patients' tissues and serum compared with controls (P<0.001). Moreover, the expression of ELMO3 was significantly associated with tumor size (P=0.020), TNM stage (P=0.017), lymph node metastasis (PP=0.045) and distance metastasis (P=0.033). ROC showed the AUC was 0.917, and the optimal cutoff value was 0.735, providing a sensitivity of 92.8% and a specificity of 84.3%. Furthermore, Kaplan-Meier analysis indicated the high expression of ELMO3 could lead to a shorter overall survival time. In multivariate analysis, ELMO3 expression (HR=3.378, 95% CI=1.326-8.587, P=0.011) was proved to be linked with the prognosis of NSCLC and might act as an independent prognostic marker.

CONCLUSION

The over-expression of ELMO3 was a potential diagnostic and prognostic marker for NSCLC.

Quantitative phosphoproteomic analysis of signaling downstream of the prostaglandin e2/g-protein coupled receptor in human synovial fibroblasts: potential antifibrotic networks

The Prostaglandin E2 (PGE2) signaling mechanism within fibroblasts is of growing interest as it has been shown to prevent numerous fibrotic features of fibroblast activation with limited evidence of downstream pathways. To understand the mechanisms of fibroblasts producing tremendous amounts of PGE2 with autocrine effects, we apply a strategy of combining a wide-screening of PGE2-induced kinases with quantitative phosphoproteomics. Our large-scale proteomic approach identified a PKA signal transmitted through phosphorylation of its substrates harboring the R(R/X)X(S*/T*) motif. We documented 115 substrates, of which 72 had 89 sites with a 2.5-fold phosphorylation difference in PGE2-treated cells than in untreated cells, where approximately half of such sites were defined as being novel. They were compiled by networking software to focus on highlighted activities and to associate them with a functional readout of fibroblasts. The substrates were associated with a variety of cellular functions including cytoskeletal structures (migration/motility), regulators of G-protein coupled receptor function, protein kinases, and transcriptional/translational regulators. For the first time, we extended the PGE2 pathway into an elaborate network of interconnecting phosphoproteins, providing vital information to a once restricted signalosome. These data provide new insights into eicosanoid-initiated cell signaling with regards to the regulation of fibroblast activation and the identification of new targets for evidenced-based pharmacotherapy against fibrosis.

Migration of dendritic cells: physical principles, molecular mechanisms, and functional implications

Dendritic cells (DCs) constitute a complex cell population that resides in both peripheral tissues and lymphoid organs. Their major function in tissues is to patrol their environment in search of danger-associated antigens to transport to lymph nodes and present to T lymphocytes. This process constitutes the first step of the adaptive immune response and relies on specific DC properties, including a high endocytic capacity as well as efficient motility in confined three-dimensional environments. Although cell motility has been widely studied, little is known on how the geometric characteristics of the environment influence DC migration and function. In this review, we give an overview of the basic physical principles and molecular mechanisms that control DC migration under confinement and discuss how such mechanisms impact the environment-patrolling capacity of DCs.