Since advance online publication, the legend to Fig 2 has been amended to remove an incorrect explanation for the KD abbreviation.The posttranslational regulation of mammalian clock proteins has been assigned a time-keeping function, but seems to have more essential roles. Here we show that c-Jun N-terminal kinase (JNK), identified by inhibitor screening of BMAL1 phosphorylation at Ser 520/Thr 527/Ser 592, confers dynamic regulation on the clock. Knockdown of JNK1 and JNK2 abrogates BMAL1 phosphorylation and lengthens circadian period in fibroblasts. Mice deficient for neuron-specific isoform JNK3 have altered behavioural rhythms, with longer free-running period and compromised phase shifts to light. The locomotor rhythms are insensitive to intensity variance of constant light, deviating from Aschoff's rule. Thus, JNK regulates a core characteristic of the circadian clock by controlling the oscillation speed and the phase in response to light.

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Single domain antibodies (sdAbs), made of natural single variable regions of camelid or cartilaginous fish antibodies, or unpaired variable regions of mouse or human IgGs, are some of the more promising biologic modalities. However, such conventional sdAbs have difficulties of either using unwieldy animals for immunization or having high affinity deficiencies. Herein, we offer a versatile method to generate rabbit variable domain of heavy chain (rVH) derived sdAbs with high affinities (K D values of single digit nM or less) and enhanced thermal stabilities (equal to or even higher than those of camelid derived sdAbs). It was found that a variety of rVH binders, including those with high affinities, were efficiently acquired using an rVH-displaying phage library produced at a low temperature of 16 °C. By a simple method to introduce an additional disulfide bond, their unfolding temperatures were increased by more than 20 °C without severe loss of binding affinity. Differential scanning calorimetry analysis suggested that this highly efficient thermal stabilization was mainly attributed to the entropic contribution and unique thermodynamic character of the rVHs.

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