Cell migration requires reposition and reshaping of the cell nucleus. The nuclear lamina is highly important for migration of both primary and
cancer cells. B-type
lamins are important for proper migration of epicardial cells and neurons and increased
lamin B to
lamin A ratio accelerates
cancer cell migration through confined spaces. Moreover, a positive association between
lamin B1 levels and
tumor formation and progression is found in various
cancer types. Still, the molecular mechanism by which B-type
lamins promote cell migration is not fully understood. To better understand this mechanism, we tested the effects of
lamin B1 on perinuclear actin organization. Here we show that induction of
melanoma cell migration leads to the formation of a cytosolic Linker of Nucleoskeleton and Cytoskeleton (LINC) complex-independent perinuclear actin rim, which has not been detected in migrating cells, yet. Significantly, increasing the levels of
lamin B1 but not the levels of
lamin A prevented perinuclear actin rim formation while accelerated the cellular migration rate. To interfere with the perinuclear actin rim, we generated a chimeric
protein that is localized to the outer nuclear membrane and cleaves perinuclear actin filaments in a specific manner without disrupting other cytosolic actin filaments. Using this tool, we found that disruption of the perinuclear actin rim accelerated the cellular migration rate in a similar manner to
lamin B1 over-expression. Taken together, our results suggest that increased
lamin B1 levels can accelerate cell migration by inhibiting the association of the nuclear envelope with actin filaments that may reduce nuclear movement and deformability.