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The mitotic spindle is the major piece of cellular machinery essential for faithful chromosome segregation. Whereas Fyn, a member of Src-family kinases, is known to be localized to the meiotic and mitotic spindle microtubules, the role of Fyn in mitotic spindle formation has not yet been completely elucidated. In this study, we studied the role of Fyn in spindle formation and effects on M-phase progression. Re-expression of Fyn induced increases in the fluorescence intensity of mitotic spindle microtubules in SYF cells having triple knock-out mutations of c-Src, c-Yes, and Fyn. Cold treatment results showed that Fyn increases the maximum length of microtubules in HeLa S3 cells in a manner dependent on Fyn kinase activity. Complete depolymerization of microtubules under cold treatment and the following release into 37 °C revealed that the increase in the microtubule length in Fyn-expressing cells may be attributed to the promotion of microtubule polymerization. After cold treatment, Fyn promotes the accumulation of EB1, which is a plus-end tracking protein and facilitates microtubule growth, in a manner dependent on the kinase activity. Furthermore, Fyn accelerates the M phase progression of cells from nocodazole arrest. These results suggest that Fyn facilitates mitotic spindle formation through the increase in microtubule polymerization, resulting in the acceleration of M-phase progression.

The issue of drug lag in Japan has been rapidly reduced in recent years, and newly approved drugs now become available on Japanese and international markets at the same time. In this context, the risk management plan (RMP) system was introduced in 2012. RMPs describe important safety concerns recognized by Japan's Pharmaceuticals and Medical Devices Agency (PMDA) and marketing authorization holders (MAHs), as well as safety measures that MAHs request healthcare professionals (HCPs) to follow. The publication of RMPs is expected to support the sharing of drug risk management among HCPs during the postmarketing phase. In addition, to encourage risk communication between HCPs and patients, the PMDA website provides drug guides for patients and other information to promote proper understanding of drugs by patients and their families and enable them to identify serious adverse drug reactions at an early stage. However, the results of surveys conducted by the PMDA in FY2014 and FY2015 revealed low levels of awareness of RMPs and drug guides for patients in hospitals and other healthcare institutions. The surveys also showed that information regarding the proper use of drugs from MAHs and the PMDA was not incorporated into practice at healthcare institutions, resulting in the repeated release of identical safety alerts. To facilitate the increased utilization of risk communication tools, the PMDA has been providing and disseminating these tools through its website. This study addresses those eŠorts and the associated challenges.