Arg links actin and microtubules

A ctin both pushes out the membrane of moving cells and links to adhesion sites to give those cells traction. But actin does not operate alone. Microtubules (MTs) are targeted to the front of the cell to deliver signals that promote actin polymerization and thus give moving cells directionality. Now, Miller et al. (page 407) report that Arg, a nonreceptor tyrosine kinase, acts as a physical link between actin and MTs that may allow this signal transfer.

Arg was known to bind and bundle actin, but the report of a MT-binding site between the two actin-binding sites is new. MTs cosediment with but are not cross-linked by Arg; cross-links do, however, form between arrays of MTs and F-actin when Arg is present. Arg staining coincides with concentrations of both F-actin and MTs...