Type I but Not Type II Calreticulin Mutations Activate the IRE1α/XBP1 Pathway of the Unfolded Protein Response to Drive Myeloproliferative Neoplasms.

Unlabelled: Approximately 20% of patients with myeloproliferative neoplasms (MPN) harbor mutations in the gene calreticulin (CALR), with 80% of those mutations classified as either type I or type II. While type II CALR-mutant proteins retain many of the Ca2+ binding sites present in the wild-type protein, type I CALR-mutant proteins lose these residues. The functional consequences of this differential loss of Ca2+ binding sites remain unexplored.

Co-mutation pattern, clonal hierarchy, and clone size concur to determine disease phenotype of SRSF2-mutated neoplasms.

Somatic mutations in splicing factor genes frequently occur in myeloid neoplasms. While SF3B1 mutations are associated with myelodysplastic syndromes (MDS) with ring sideroblasts, SRSF2 mutations are found in different disease categories, including MDS, myeloproliferative neoplasms (MPN), myelodysplastic/myeloproliferative neoplasms (MDS/MPN), and acute myeloid leukemia (AML). To identify molecular determinants of this phenotypic heterogeneity, we explored molecular and clinical features of a prospective cohort of 279 SRSF2-mutated cases selected from a population of 2663 patients with myeloid neoplasms.

Combined loss of function of two different loci of miR-15/16 drives the pathogenesis of acute myeloid leukemia.

Double knockout of the two miR-15/16 loci in mouse resulted in the development of acute myeloid leukemia (AML). This result suggested that, at least, a fraction of human AMLs could be due to a similar mechanism. We analyzed the role of the two miR-15/16 clusters in 93 myelodysplastic syndrome (MDS) patients divided in three subgroups: patients with MDS, patients with MDS before transforming into AML (MDS-T), and patients with AML evolving from MDS (MDS-AML).

Alzheimer disease and platelets: how's that relevant.

Alzheimer Disease (AD) is the most common neurodegenerative disorder worldwide, and account for 60% to 70% of all cases of progressive cognitive impairment in elderly patients. At the microscopic level distinctive features of AD are neurons and synapses degeneration, together with extensive amounts of senile plaques and neurofibrillars tangles. The degenerative process probably starts 20-30 years before the clinical onset of the disease.

Epinephrine-mediated protein kinase C and Rap1b activation requires the co-stimulation of Gz-, Gq-, and Gi-coupled receptors.

We have recently shown that ADP-induced activation of protein kinase C (PKC) requires the co-stimulation of both P2Y1 and P2Y12 receptors. In this work, we show that inhibition of ADP-mediated phosphorylation of pleckstrin, the main PKC substrate, caused by antagonists of the P2Y12 receptor can be reversed by stimulation of the α2-adrenergic receptor by epinephrine. However, we also observed that addition of epinephrine alone caused a marked phosphorylation of pleckstrin.

Identification and biochemical characterization of Rap2C, a new member of the Rap family of small GTP-binding proteins.

The Rap family of small GTP-binding proteins is composed by four different members: Rap1A, Rap1B, Rap2A and Rap2B. In this work we report the identification and characterization of a fifth member of this family of small GTPases. This new protein is highly homologous to Rap2A and Rap2B, binds labeled GTP on nitrocellulose, and is recognized by a specific anti-Rap2 antibody, but not by an anti-Rap1 antibody.