Phosphodiesterase type 4 anchoring regulates cAMP signaling to Popeye domain-containing proteins.

Cyclic AMP is a ubiquitous second messenger used to transduce intracellular signals from a variety of Gs-coupled receptors. Compartmentalisation of protein intermediates within the cAMP signaling pathway underpins receptor-specific responses. The cAMP effector proteins protein-kinase A and EPAC are found in complexes that also contain phosphodiesterases whose presence ensures a coordinated cellular response to receptor activation events. Popeye domain containing (POPDC) proteins are the most recent class of cAMP effectors to be identified and have crucial roles in cardiac pacemaking and conduction. We report the first observation that POPDC proteins exist in complexes with members of the PDE4 family in cardiac myocytes. We show that POPDC1 preferentially binds the PDE4A sub-family via a specificity motif in the PDE4 UCR1 region and that PDE4s bind to the Popeye domain of POPDC1 in a region known to be susceptible to a mutation that causes human disease. Using a cell-permeable disruptor peptide that displaces the POPDC1-PDE4 complex we show that PDE4 activity localized to POPDC1 modulates cycle length of spontaneous Ca2+ transients firing in intact mouse sinoatrial nodes

Obsessive-compulsive disorder in UK clozapine-treated schizophrenia and schizoaffective disorder : a cause for clinical concern

Original article can be found at : http://jop.sagepub.com/ Copyright Sage [Full text of this article is not available in the UHRA]The association between schizophrenia and obsessive-compulsive disorder (OCD) is complex. This study systematically examined a UK cohort of clozapine-treated individuals with schizophrenia/schizoaffective disorder. Fourteen of 59 cases (24%) scored positively on item H of the Mini-International Neuropsychiatric Interview (MINI) for OCD. The mean Yale— Brown Obsessive-Compulsive Scale (Y-BOCS) score in MINI-positive cases was 17.6 (SD ± 6.3). Sixty-four percent scored 16 or more on the Y-BOCS, representing clinically meaningful illness severity. Seven (50%) patients with OCD had previously received the diagnosis by their treating clinicians and were already receiving with selective serotonin re-uptake inhibitors (SSRIs) treatment. OCD cases scored significantly worse than their non-OCD counterparts on the Abnormal Involuntary Movement Scale (P = 0.01) and the Simpson Angus Scale (SAS; P = 0.01). There was also a non-significant trend toward higher ratings for OCD cases on the Clinical Global Impression-Schizophrenia scale (P = 0.06). Comparing the OCD cases taking SSRI (n = 7) with those not on SSRI (n = 7), significant differences emerged on the SAS (P = 0.03). Our results suggest that OCD is common among patients receiving clozapine for schizophrenic disorders and that the comorbidity is associated with greater motoric impairment. The role of medication in this condition remains unclear.Peer reviewe