June 2011 | Volume 193, No. 6
In This Issue
People & Ideas
- EB1 promotes microtubule dynamics by recruiting Sentin in Drosophila cells
The microtubule plus end regulator EB1 brings Sentin and possibly a microtubule polymerase to microtubule plus ends to promote microtubule dynamics.
- Direct regulation of Treslin by cyclin-dependent kinase is essential for the onset of DNA replication
Phosphorylation of human Treslin by Cdk is essential for its association with TopBP1 and for the initiation of DNA replication in S phase.
- The nucleoporin RanBP2 tethers the cAMP effector Epac1 and inhibits its catalytic activity
Direct interaction between the catalytic domain of Epac1 and the nuclear pore component RanBP2 blocks Epac1 catalytic activity and downstream cAMP signaling.
- Aurora A kinase activity influences calcium signaling in kidney cells
Aurora A is abnormally expressed and activated in cells lining cysts associated with polycystic kidney disease and can phosphorylate and inactivate polycystin 2.
- The cortical protein Lte1 promotes mitotic exit by inhibiting the spindle position checkpoint kinase Kin4
Lte1 directly inhibits Kin4 activity and restricts its binding to the mother spindle pole body, which allows proper mitotic exit of cells with a correctly aligned spindle.
- Bub1 overexpression induces aneuploidy and tumor formation through Aurora B kinase hyperactivation
Hyperactivated Aurora B kinase is a primary mediator of Bub1 overexpression-induced aneuploidy and tumorigenesis in mice.
- Septin filaments exhibit a dynamic, paired organization that is conserved from yeast to mammals
Polarized fluorescence microscopy reveals that septins across diverse species assemble into similar higher-order structures consisting of dynamic, paired filaments.
- SLAIN2 links microtubule plus end–tracking proteins and controls microtubule growth in interphase
SLAIN2’s interactions with multiple different microtubule plus end–tracking proteins stimulate processive microtubule polymerization and ensure proper microtubule organization.
- Cbp3–Cbp6 interacts with the yeast mitochondrial ribosomal tunnel exit and promotes cytochrome b synthesis and assembly
A complex specifically required for the biogenesis of the respiratory chain component cytochrome b binds to the tunnel exit of yeast mitochondrial ribosomes to coordinate protein synthesis and assembly.
- Type XII collagen regulates osteoblast polarity and communication during bone formation
Type XII collagen–null mice have fragile bones with disorganized collagen fiber arrangement, decreased bone matrix formation, and delayed osteoblast differentiation.