Download MendeleyCrystal structure of Lamellipodin implicates diverse functions in actin polymerization and Ras signaling.
Chang, Y.C., Zhang, H., Brennan, M.L., Wu, J.(2013) Protein Cell 4: 211-219
- PubMed: 23483482
- DOI: https://doi.org/10.1007/s13238-013-2082-5
- Primary Citation of Related Structures:
4GMV, 4GN1 - PubMed Abstract:
The adapter protein Lamellipodin (Lpd) plays an important role in cell migration. In particular, Lpd mediates lamellipodia formation by regulating actin dynamics via interacting with Ena/VASP proteins. Its RA-PH tandem domain configuration suggests that like its paralog RIAM, Lpd may also mediate particular Ras GTPase signaling. We determined the crystal structures of the Lpd RA-PH domains alone and with an N-terminal coiled-coil region (cc-RA-PH). These structures reveal that apart from the anticipated coiled-coil interaction, Lpd may also oligomerize through a second intermolecular contact site. We then validated both oligomerization interfaces in solution by mutagenesis. A fluorescence-polarization study demonstrated that Lpd binds phosphoinositol with low affinity. Based on our crystallographic and biochemical data, we propose that Lpd and RIAM serve diverse functions: Lpd plays a predominant role in regulating actin polymerization, and its function in mediating Ras GTPase signaling is largely suppressed compared to RIAM.
Organizational Affiliation:
Department of Developmental Therapeutics, Fox Chase Cancer Center, 333 Cottman Avenue, Philadelphia, PA 19111, USA.
