The cell-surface glycoprotein basigin – also known as EMMPRIN – enhances growth and invasiveness of human metastatic tumours by stimulating secretion of matrix metalloproteinases (MMPs), which remodel the extracellular matrix. Now, however, Kathryn Curtin and colleagues report that basigin can also have dramatic effects on internal cell architecture (see ). They show that the Drosophila homologue, D-basigin, promotes integrin-dependent cytoskeletal rearrangements and lamellipodia formation in cultured insect cells. In vivo, loss of D-basigin in photoreceptors leads to misplaced nuclei and other structural changes that suggest disruption of the cytoskeleton; these changes can be rescued by fly or mouse basigin. The authors also report that D-basigin colocalizes with integrins in cultured insect cells and in the fly visual system, and partly colocalizes with actin in cultured insect cells, possibly indirectly through its interaction with integrins. Most importantly, D-basigin interacts genetically with integrins to affect the structure of photoreceptor cells in flies. The authors therefore conclude that D-basigin regulates the intracellular architecture of Drosophila cells and does so in an integrin-dependent but MMP-independent manner.
