Microtubules derived from the Golgi (Golgi MTs) have been implicated to play critical roles in persistent cell migration, but the underlying mechanisms remain elusive, partially due to the lack of direct observation of Golgi MT‐dependent vesicular trafficking. Here, using super‐resolution stochastic optical reconstruction microscopy (STORM), we discovered that post‐Golgi cargos are more enriched on Golgi MTs and also surprisingly move much faster than on non‐Golgi MTs. We found that, compared to non‐Golgi MTs, Golgi MTs are morphologically more polarized toward the cell leading edge with significantly fewer inter‐MT intersections. In addition, Golgi MTs are more stable and contain fewer lattice repair sites than non‐Golgi MTs. Our STORM/live‐cell imaging demonstrates that cargos frequently pause at the sites of both MT intersections and MT defects. Furthermore, by optogenetic maneuvering of cell direction, we demonstrate that Golgi MTs are essential for persistent cell migration but not for cells to change direction. Together, our study unveils the role of Golgi MTs in serving as a group of “fast tracks” for anterograde trafficking of post‐Golgi cargos.

We propose SMART FRAP, a robust FRAP quantitative analysis method that is insensitive to varied experimental conditions and condensate properties. SMART FRAP can not only accurately and quantitatively determine the...

DNA double-strand break (DSB) is the most dangerous type of DNA damage. In addition, DSBs are also common consequences of various therapeutic and genetic modifications. Therefore, quantification of DSB is of great importance in many fields including DNA damage repair, cancer therapy, gene editing, and radiation biology. Current methods are either low-throughput, laborious, or high cost. Here, we developed dc-BLIS (digital counting of breaks labeling in situ), a new method that can rapidly and precisely quantify the number of intracellular DSBs at a low cost by digital polymerase chain reaction. Using dc-BLIS, we quantified and compared the amount of DSBs induced by anti-cancer drugs, Cas9 variants, and different radiation doses, proving the capacity of dc-BLIS to quantify DSBs. We propose that dc-BLIS is suitable for various application scenes that require rapid and precise quantification of DSBs, including drug screening, gene-editing tool modification, and radiation effect assessment.

The trans-luminal LINC (Linker of Nucleoskeleton and Cytoskeleton) complex plays a central role in nuclear mechanotransduction by coupling the nucleus with cytoskeleton. High spatial density and active dynamics of LINC complex have hindered its precise characterization for the understanding of underlying mechanisms how the linkages sense and respond to mechanical stimuli. In this study, we focus on SUN2, a core component of LINC complex interconnecting the nuclear lamina and actin cytoskeleton and apply single molecule super-resolution imaging to reveal how SUN2 responds to actomyosin contractility. Using stochastic optical reconstruction microscopy (STORM), we quantitated the distribution pattern and density of SUN2 on the basal nuclear membrane. We found that SUN2 undergoes bidirectional translocation between ER and nuclear membrane in response to actomyosin contractility, suggesting that dynamic constrained force on SUN2 is required for its proper distribution. Furthermore, single molecule imaging unveils interesting dynamics of SUN2 molecules that are regulated by both actomyosin contractility and laminA/C network, whereas SUN2 oligomeric states are not affected by actomyosin contractility. Lastly, the mechanical response of SUN2 to actomyosin contractility was found to regulate expression of mechano-sensitive genes located in lamina-associated domains (LADs) and perinuclear heterochromatin. Taken together, our results reveal how SUN2 responds to mechanical cues at the single-molecule level, providing new insights into the mechanism of nuclear mechanotransduction.