CARMA1 coiled-coil domain is involved in the oligomerization and subcellular localization of CARMA1 and is required for T cell receptor-induced NF-kappa B activation
JOURNAL OF BIOLOGICAL CHEMISTRY
Authors: Tanner, Matthew J.; Hanel, Walter; Gaffen, Sarah L.; Lin, Xin
Abstract
T lymphocyte (T cell) activation and proliferation is induced by the activation of multiple signal transduction pathways. Earlier studies indicate that CARMA1, a Caspase Recruitment Domain (CARD) and Membrane-associated GUanylate Kinase domain (MAGUK)-containing scaffold protein, plays an essential role in NF-kappa B activation induced by the costimulation of T cell receptor (TCR) and CD28 molecules. However, the molecular mechanism by which CARMA1 mediates TCR-CD28 costimulation-induced NF-kappa B activation is not fully understood. Here we show that CARMA1 is constitutively oligomerized. This oligomerization of CARMA1 is through its Coiled-coil domain. Disruption of the predicted structure of the Coiled-coil domain of CARMA1 impaired its oligomerization and, importantly, abrogated CARMA1-mediated NF-kappa B activation. Interestingly, disruption of the CC1 domain abrogates CARMA1 localization, whereas disruption of the CC2 domain seems to inhibit CARMA1 self-association. Together, our results demonstrate that the oligomerization of CARMA1 is required for TCR-induced NF-kappa B activation.
ACTH-secreting Pancreatic Neoplasms Associated With Cushing Syndrome Clinicopathologic Study of 11 Cases and Review of the Literature
AMERICAN JOURNAL OF SURGICAL PATHOLOGY
Authors: Maragliano, Roberta; Vanoli, Alessandro; Albarello, Luca; Milione, Massimo; Basturk, Olca; Klimstra, David S.; Wachtel, Antonio; Uccella, Silvia; Vicari, Emanuela; Milesi, Marina; Davi, Maria Vittoria; Scarpa, Aldo; Sessa, Fausto; Capella, Carlo; La Rosa, Stefano
Abstract
Adrenocorticotropic hormone (ACTH)-secreting pancreatic neuroendocrine tumors (PanNETs), although rare, are responsible for about 15% of ectopic Cushing syndrome (CS). They represent a challenging entity because their pre-operatory diagnosis is frequently difficult, and clear-cut morphologic criteria useful to differentiate them from other types of PanNETs have not been defined. Ectopic ACTH secretion associated with CS can also be rarely due to pancreatic acinar cell carcinoma (ACC) and pancreatoblastoma, rare tumor types with morphologic features sometimes overlapping those of PanNETs and, for this reason, representing a diagnostic challenge for pathologists. We herein describe the clinicopathologic and immunohistochemical features of 10 PanNETs and 1 ACC secreting ACTH and associated with CS together with an extensive review of the literature to give the reader a comprehensive overview on ACTH-producing pancreatic neoplasms. ACTH-secreting PanNETs are aggressive neoplasms with an immunohistochemical profile that partially overlaps that of pituitary corticotroph adenomas. They are generally large and well-differentiated neoplasms without distinctive histologic features but with signs of aggressiveness including vascular and perineural invasion. They are more frequent in female individuals with a mean age of 42 years. At 5 and 10 years after diagnosis, 35% and 16.2% of patients, respectively, were alive. ACTH-secreting ACCs and pancreatoblastomas are very aggressive pediatric tumors with a poor prognosis. Using an appropriate immunohistochemical panel including ACTH, beta-endorphin, trypsin, and BCL10 it is possible to recognize ACTH-secreting PanNETs and to distinguish them from the very aggressive ACTH-secreting ACCs.