Magic™ Anti-ENSA (full length) polyclonal antibody

Protein phosphatase 2A (PP2A) plays important roles in controlling mitosis in all eukaryotic cells. The form of PP2A that controls mitosis is associated with a conserved regulatory subunit that is called B55 in vertebrates and Cdc55 in budding yeast. The activity of this form of PP2A can be inhibited by binding of conserved Igo/ ENSA proteins. Although the mechanisms that activate Igo/ ENSA to bind and inhibit PP2A are well understood, little is known about how Igo/ Ensa are inactivated. Here, we have analyzed regulation of Igo/ ENSA in the context of a checkpoint pathway that links mitotic entry to membrane growth in budding yeast. Protein kinase C (Pkc1) relays signals in the pathway by activating PP2A(Cdc55). We discovered that constitutively active Pkc1 can drive cells through a mitotic checkpoint arrest, which suggests that Pkc1-dependent activation of PP2A(Cdc55) plays a critical role in checkpoint signaling. We therefore used mass spectrometry to determine how Pkc1 modifies the PP2A(Cdc55) complex. This revealed that Pkc1 induces changes in the phosphorylation of multiple subunits of the complex, as well as dissociation of Igo/ ENSA. Pkc1 directly phosphorylates Cdc55 and Igo/ ENSA, and phosphorylation site mapping and mutagenesis indicate that phosphorylation of Cdc55 contributes to Igo/ ENSA dissociation. Association of Igo2 with PP2A(Cdc55) is regulated during the cell cycle, yet mutation of Pkc1-dependent phosphorylation sites on Cdc55 and Igo2 did not cause defects in mitotic progression. Together, the data suggest that Pkc1 controls PP2A(Cdc55) by multiple overlapping mechanisms.

Alternaria leaf spot caused by Alternaria alternata (Fries.) Kiessler was found on sow thistle (Sonchus oleraceus L.) and field bindweed (Convolvulus arvensis L.) in the experimental station of ENSA (Ecole Nationale Superieure d'Agronomie) in Algiers, Algeria, during the winter of 2016. Necrotic spots in the form of concentric circles were observed on the leaves of both weeds with disease incidence of approximately 70% and disease severity ranging from 50% to 70%. Fungi were isolated from the infected leaves and identified as A. alternata, based on morphological and molecular analyses (using genetic marker internal transcribed spacer, ITS of rDNA). Pathogenicity tests confirmed that A. alternata is the causing agent of leaf spot disease of sow thistle and field bindweed in accordance with the original symptoms. To the best of our knowledge, this is the first report of sow thistle and field bindweed naturally infected by A. alternata in Algeria.