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[Purpose/significance] This paper aims to understand the evolution characteristics and the structure of transnational scientific collaborative network of knowledge management, and find the shortage and advantage of China. [Method/process] Through analytical methods of statistics, ecology, scientometrics and geography, the article conducted a systematic analysis on the evolution characteristics and the structure of transnational scientific collaborative network of knowledge management which was composed of the literature on knowledge management from SSCI-E and SCI database in the Web of Science during 2001-2015. [Result/conclusion] International collaborative participants are mainly distributed in Asia, Australia, and Europe and the United States. Bilateral cooperation is the main mode of international cooperation in the knowledge management. USA and UK play leading roles in the international collaborative network of knowledge management. USA is the main partner nation. China is America’s most important partner, and its leading ability is out of step with its scientific productivity.

Cell polarity is essential for ameloblast differentiation and enamel formation. Smurf1 can mediate cell polarization through ubiquitination degradation of specific substrates. But it remains unclear whether Smurf1 could regulate ameloblast polarity and the underlying mechanism. Here, immuno‐fluorescence staining and RT‐qPCR were applied to detect the expression of Smurf1 and F‐actin. A mouse lower incisor defect model was constructed. Scanning electron microscope, rat lower incisor culture, western blot, wound healing assay and trans‐well migration assay were performed to detect the influence of Smurf1 knockdown on ameloblast. IF double staining, western blot and co‐immunoprecipitation were conducted to detect the interaction between Smurf1 and RhoA. The in vivo experiment was also performed. We found that Smurf1 was mainly expressed in the membrane and cell cortex of ameloblast, similar to F‐actin. Smurf1 expression increased along ameloblast polarization and differentiation. After knocking down Smurf1, the cytoskeleton and cell morphology changed and the cell polarity was damaged. Smurf1 regulated ameloblast polarity through ubiquitination degradation of activated RhoA in vitro. Local knockdown of Smurf1 in rat lower incisor ameloblast resulted in ameloblast polarity loss, enamel matrix secretion disorder and chalky enamel, but RhoA inhibitor Y‐27632 could reverse this effect. Collectively, Smurf1 could regulate the polarization of ameloblast through ubiquitination degradation of activated RhoA, which contributed to the knowledge of tooth development and provided new research ideas for cell polarity. [ABSTRACT FROM AUTHOR]