Diagrams of eukaryotic cells often show the nucleus in the centre of the cell, but the position of the nucleus actually changes during certain developmental stages and cellular events. For example, during the polarisation that precedes fibroblast migration, the nucleus moves away from the future leading edge of the cell. This nuclear movement involves nesprin-2G (a nuclear envelope spectrin repeat protein) and the SUN-domain protein SUN2, which are components of the linker of nucleoskeleton and cytoskeleton (LINC) complex that form transmembrane actin-associated nuclear (TAN) lines at the nuclear envelope. Now, on page , Edgar Gomes and colleagues report that the nuclear envelope protein spindle-associated membrane protein 1 (Samp1, also known as NET5 and TMEM201) is also required for nuclear movement in migrating fibroblasts. By using siRNA knockdown, the authors show that Samp1 is involved in centrosome orientation and nuclear movement during fibroblast polarisation and migration in wounded NIH-3T3 monolayers. They report that Samp1 is a component of TAN lines and that it associates with both SUN2 and lamin A/C. Finally, the authors show that the maintenance of Samp1 at the nuclear envelope requires lamin A/C. Together, these results suggest that Samp1 is involved in the regulation of the LINC complex during nuclear movement and cell migration in fibroblasts.
