Highlights d Structure-guided design of PARP inhibitors d Identification of a potent and selective PARP11 inhibitor (ITK7) d ITK7 inhibits PARP11 auto-MARylation in cells d ITK7 causes PARP11 to dissociate from the nuclear envelope

We synthesized the first multifunctionalized phosphoinositide polyphosphate derivatives featuring ap hotoremovable protecting group ("cage"), ap hoto-crosslinkable diazirine group,a nd at erminal alkyne group useful for click chemistry.W ed emonstrate that the lipid derivatives readily enter cells.A fter photo-crosslinking,c ell fixation and fluorescent tagging via click chemistry,wedetermined the intracellular location of the lipid derivatives before and after uncaging of the lipids.W ef ind that there is rapid trafficking of PI(3,4)P 2 and PI(3,4,5)P 3 derivatives to the plasma membrane,o pening the intriguing possibility that there is active transport of these lipids involved. We employed the photo-crosslinking and click chemistry functions to analyze the proteome of PI(3,4,5)P 3binding proteins.From the latter,wevalidated by RNAi that the putative lipid binding proteins ATP11A and MPP6 are involved in the transport of PI(3,4,5)P 3 to the plasma membrane.

No abstract

Four human Ankrd2 transcripts, reported in the Ensembl database, code for distinct protein isoforms (360, 333, 327 and 300 aa), and so far, their existence, specific expression and localization patterns have not been studied in detail. Ankrd2 is preferentially expressed in the slow fibers of skeletal muscle. It is found in both the nuclei and the cytoplasm of skeletal muscle cells, and its localization is prone to change during differentiation and upon stress. Ankrd2 has also been detected in the heart, in ventricular cardiomyocytes and in the intercalated disks (ICDs). The main objective of this study was to distinguish between the Ankrd2 isoforms and to determine the contribution of each one to the general profile of Ankrd2 expression in striated muscles. We demonstrated that the known expression and localization pattern of Ankrd2 in striated muscle can be attributed to the isoform of 333 aa which is dominant in both tissues, while the designated cardiac and canonical isoform of 360 aa was less expressed in both tissues. The 360 aa isoform has a distinct nuclear localization in human skeletal muscle, as well as in primary myoblasts and myotubes. In contrast to the isoform of 333 aa, it was not preferentially expressed in slow fibers and not localized to the ICDs of human cardiomyocytes. Regulation of the expression of both isoforms is achieved at the transcriptional level. Our results set the stage for investigation of the specific functions and interactions of the Ankrd2 isoforms in healthy and diseased human striated muscles.