Affinity
for target proteins and target selectivity are among the most important factors
in drug development. The authors previously developed a fluorescence
recovery-based polo-like kinase 1 (Plk1) kinase domain-directed binding assay
using an ATP-competitive Plk1 inhibitor-based fluorescent probe. Herein the
authors expanded the assay system to other Plk family members by successfully
constructing novel binding assay methodology for the kinase domains of Plk2 and
Plk3. The authors also demonstrated that polo-box domain-directed affinity
evaluation against full-length Plk’s 1–3 requires much higher affinity probes
to overcome auto-inhibition.
Dab1 is an intracellular
adaptor protein, and its tyrosine phosphorylation plays an important role in
various events of brain development. Loss of Dab1 has been associated with the
onset of neuropsychiatric disorders in humans. The authors demonstrate a novel
mechanism for Dab1 phosphorylation by EphA4, a member of the receptor tyrosine
kinase family. EphA4-mediated Dab1 phosphorylation requires autophosphorylation
of EphA4 and activity of Src family tyrosine kinases. Cultured neurons
expressed EphA4 and Dab1, but activation of EphA4 by ephrin A5 did not induce
Dab1 phosphorylation, suggesting that Dab1 is localized in a different
compartment in them.
The
Accelerated Approval (AA) Program of the United States (US) Food and Drug
Administration (FDA) expedites access to new drugs for serious conditions,
while Japan's conditional approval system remains underutilized. The authors
analyzed postmarketing requirement compliance for AA drugs and their approval
timing in Japan. These findings indicate that while the US AA program is
well-managed, Japan needs improvements to actively utilize its conditional
approval system, enabling rapid introduction of innovative drugs and timely confirmation
of their efficacy and safety.
[Highlighted Paper selected
by Editor-in-Chief]
Vascular smooth muscle contraction has two
phases, an early phase and a sustained phase. Using ionomycin, which increases cytosolic free Ca2+
concentration ([Ca2+]i) without membrane depolarization or
receptor stimulation, the authors demonstrated that the early phase of contraction is due to activation of myosin
light chain kinase (MLCK) via Ca2+/calmodulin (CaM), and the
sustained phase is due to activation of the CaM-independent RhoA/ Rho-associated kinase (ROCK) pathway
via proline-rich tyrosine kinase 2 (Pyk2). These findings suggest Pyk2 may be a new therapeutic
target for cardiovascular disease.
18-β-Glycyrrhetinic
acid (GA) is widely incorporated into hair care cosmetic products as an
anti-inflammatory agent to maintain a healthy scalp. This study revealed that
GA possesses anti-inflammatory effects on the scalp as well as novel effects on
hair, including the stimulation of proliferation in human dermal papilla cells
and human outer root sheath cells, and the inhibition of 5α-reductase.
Promoting the proliferation of these two types of cells is influential in
forming thicker and longer hair, while inhibiting 5α-reductase is effective in
improving androgenetic alopecia.