Association of the Leukocyte Plasma Membrane with the Actin Cytoskeleton through Coiled Coil-mediated Trimeric Coronin 1 Molecules

Coronin 1 is a member of the coronin protein family specifically expressed in leukocytes and accumulates at sites of rearrangements of the F-actin cytoskeleton. Here, we describe that coronin 1 molecules are coiled coil-mediated homotrimeric complexes, which associate with the plasma membrane and with the cytoskeleton via two distinct domains. Association with the cytoskeleton was mediated by trimerization of a stretch of positively charged residues within a linker region between the N-terminal, WD repeat-containing domain and the C-terminal coiled coil. In contrast, neither the coiled coil nor the positively charged residues within the linker domain were required for plasma membrane binding, suggesting that the N-terminal, WD repeat-containing domain mediates membrane interaction. The capacity of coronin 1 to link the leukocyte cytoskeleton to the plasma membrane may serve to integrate outside-inside signaling with modulation of the cytoskeleton.