High impact information on pim

• Our observations suggest that Pimples and Three rows act during mitosis to release the cohesion between sister centromeres [1].
• Separation of sister chromatids in mitosis requires the Drosophila pimples product, a protein degraded after the metaphase/anaphase transition [1].
• Mutations in the Drosophila genes pimples and three rows result in a defect of sister chromatid separation during mitosis [1].
• Therefore, we have screened for genetic loci that modify the aberrant phenotypes caused by overexpression of the regulatory separase complex subunits Pimples/securin and Three rows in Drosophila [2].
• Moreover, cells arrested in mitosis before sister chromatid separation (by colcemid or by mutations in fizzy/CDC20) fail to degrade PIM [3].

Biological context of pim

• Nondegradable PIM with a mutant destruction box can rescue sister chromatid separation in pim mutants but only when expressed at low levels [3].
• Degradation of Drosophila PIM regulates sister chromatid separation during mitosis [3].
• PIM accumulates during interphase and is degraded rapidly during mitosis [3].

Anatomical context of pim

• High-resolution analysis shows that the cytoskeleton forms from microvilli-like pimples that project actin filaments into the cytoplasm [4].
• When cultured in the presence of jasplakinolide, an agent that prevents filament disassembly, pimples elongate to form microvilli containing a core of crosslinked filaments [5].
• During bristle development the emerging bristle shaft, socket cell, and the apical surface of thoracic epithelial cells form tiny protuberances or pimples that contain electron-dense material located on the cytoplasmic surface of the pimple tip [5].

Associations of pim with chemical compounds

• Whereas these securins are known to form a complex with separins, we show that PIM associates in vivo with THR, which does not contain the conserved separin domain [3].

Other interactions of pim

• Since it has been shown that active cdc2 is required to maintain the arrest seen in fzy embryos we wished to determine if pim+ and thr+ were also required [6].
• Drosophila separase associates with regulatory subunits encoded by the pimples and three rows genes [7].
• Furthermore, as pimples and microvilli form in the absence of both forked and fascin crossbridges, we also conclude that neither of these crossbridges account for core bundle formation in microvilli, but there must exist a third, as yet unidentified crossbridge in this system [5].

References