Sleep need, the key regulator of sleep homeostasis, is indicated and controlled by phosphorylation of threonine 221 in salt-inducible kinase 3.

Sleep need drives sleep and plays a key role in homeostatic regulation of sleep. So far sleep need can only be inferred by animal behaviors and indicated by electroencephalography (EEG). Here we report that phosphorylation of threonine (T) 221 of the salt-inducible kinase 3 (SIK3) increased the catalytic activity and stability of SIK3. T221 phosphorylation in the mouse brain indicates sleep need: more sleep resulting in less phosphorylation and less sleep more phosphorylation during daily sleep/wake cycle and after sleep deprivation (SD). Sleep need was reduced in SIK3 loss of function (LOF) mutants and by T221 mutation to alanine (T221A). Rebound after SD was also decreased in SIK3 LOF and T221A mutant mice. By contrast, SIK1 and SIK2 do not satisfy criteria to be both an indicator and a controller of sleep need. Our results reveal SIK3-T221 phosphorylation as a chemical modification which indicates and controls sleep need.

Kallikrein-related peptidase-8 (KLK8) aggravated hypoxia-induced right ventricular hypertrophy by targeting P38 MAPK/P53 signaling pathway.

Right ventricular (RV) hypertrophy and further heart failure are major co-morbidities, resulting in the premature death of patients with hypoxic pulmonary hypertension (HPH). The regulatory effects of kallikrein-related peptidase (KLK) family members on cardiac function have been extensively studied. However, to the best of the authors' knowledge, the regulatory effects of KLK8 on RV hypertrophy caused by HPH have yet to be reported. The aim of the present study was to assess KLK8 expression in the RV tissue of HPH-modeled rats, and to further explore the effects and underlying mechanism of KLK8 in regulating the hypertrophy of hypoxia-induced H9c2 cardiomyocytes. In HPH model rats, increases in the right ventricle hypertrophy index, the right ventricular systolic pressure, cardiac output, as well as pulmonary artery wall thickness were observed. Western blot analysis revealed that KLK8 expression and MAPK/p53 signaling activity were enhanced in the RVs of rats in an RV HPH rat model. In hypoxia-induced H9c2 cardiomyocytes, KLK8 overexpression promoted cardiomyocyte hypertrophy, whereas KLK8 silencing showed the opposite results. KLK8 overexpression increased the expression levels of ventricular hypertrophy markers, including atrial natriuretic peptide, brain natriuretic peptide and myosin heavy chain 7, which were blocked upon addition of the p38 MAPK inhibitor, SB202190. Conversely, KLK8 silencing caused a decrease in the expression levels of the ventricular hypertrophy markers, which were further reduced via inhibition of the p38 MAPK/p53 signaling pathway. Taken together, the results of the present study have shown that KLK8 may subtly regulate RV hypertrophy, and therefore KLK8 may be a promising therapeutic target for treating HPH-induced RV hypertrophy.

Recurring sequence-structure motifs in (ßα)8-barrel proteins and experimental optimization of a chimeric protein designed based on such motifs.

An interesting way of generating novel artificial proteins is to combine sequence motifs from natural proteins, mimicking the evolutionary path suggested by natural proteins comprising recurring motifs. We analyzed the ßα and αß modules of TIM barrel proteins by structure alignment-based sequence clustering. A number of preferred motifs were identified. A chimeric TIM was designed by using recurring elements as mutually compatible interfaces. The foldability of the designed TIM protein was then significantly improved by six rounds of directed evolution. The melting temperature has been improved by more than 20°C. A variety of characteristics suggested that the resulting protein is well-folded. Our analysis provided a library of peptide motifs that is potentially useful for different protein engineering studies. The protein engineering strategy of using recurring motifs as interfaces to connect partial natural proteins may be applied to other protein folds.

Potential for intensive volunteering to promote the health of older adults in fair health.

Volunteer service opportunities for older adults may soon be expanded. Although volunteering is thought to provide health benefits for healthier older adults, it is not known whether older adults in less than very good health are suitable candidates for high-intensity volunteering and can derive health benefits. This manuscript presents a prospective analysis of 174 older adult volunteers serving in Experience Corps Baltimore, a high-intensity senior volunteer program in Baltimore, Maryland. Volunteers served > or =15 h per week, for a full school year, in elementary schools helping children with reading and other skills between 1999 and 2002. Volunteers were assessed with standardized questionnaires and performance-based testing including grip strength, walking speed, chair stand speed, and stair-climbing speed prior to school volunteering and at the end of the school year. Results were stratified by health status. Among 174 volunteers, 55% initially reported "good" and 12% "fair" or "poor" health status. At baseline, those in fair health reported higher frequencies of disease and disability than volunteers in excellent or very good health. After volunteering, a majority of volunteers in every baseline health status category described increased strength and energy. Those in fair health were significantly more likely to display improved stair-climbing speed than those in good or excellent/very good health (100.0% vs. 53.4% vs. 37.5%, p = 0.05), and many showed clinically significant increases in walking speed of >0.5 m/s. Satisfaction and retention rates were high for all health status groups. Clinicians should consider whether their patients in fair or good health, as well as those in better health, might benefit from high-intensity volunteer programs. Productive activity such as volunteering may be an effective community-based approach to health promotion for older adults.