The current move toward a presidential debate highlighting science and technology may at least provide the impetus for political discussion in these areas to go beyond hot button issues.
Volume 15 Issue 3, March 2008
News & Views
Assembly of the 34-subunit, 2.5 megadalton 26S proteasome starts with formation of the seven-membered α-ring. A set of newly identified proteasome chaperones serves as a clamp to seal α-rings with the correct composition. By regulating the efficiency and outcome of this crucial step in proteasome biogenesis, these dedicated proteasome chaperones apparently partake in the stress response and in adaptation to intracellular proteolysis needs.
The ankyrin repeats of the G9a and GLP histone methyltransferases have now been shown to be binding modules for mono- and dimethyllysine histone H3 lysine 9 (H3K9), revealing a new function for an ankyrin repeat domain and showing that a polypeptide chain can both create and recognize the same histone mark.
The compositional complexity of the spliceosome creates a serious obstacle for its experimental analysis. Purification of a compositionally defined splicing complex C capable of completing the second step of splicing in the absence of additional proteins opens the door for future mechanistic and structural analyses.
The kinase regulatory-loop binding (KRLB) region of insulin receptor substrate 2 was originally thought to be a new type of domain with binding properties similar to phosphotyrosine binding (PTB) domains. A crystallographic study now shows that KRLB is actually a short peptide segment that binds to the insulin receptor using an extended series of contacts that mimic both autoinhibitory loop and ATP binding to its catalytic cleft.