Download MendeleyStructure of the Integrin {alpha}IIb Transmembrane Segment.
Lau, T.L., Dua, V., Ulmer, T.S.(2008) J Biol Chem 283: 16162-16168
- PubMed: 18417472
- DOI: https://doi.org/10.1074/jbc.M801748200
- Primary Citation of Related Structures:
2K1A - PubMed Abstract:
Integrin cell-adhesion receptors transduce signals bidirectionally across the plasma membrane via the single-pass transmembrane segments of each alpha and beta subunit. While the beta3 transmembrane segment consists of a linear 29-residue alpha-helix, the structure of the alphaIIb transmembrane segment reveals a linear 24-residue alpha-helix (Ile-966 -Lys-989) followed by a backbone reversal that packs Phe-992-Phe-993 against the transmembrane helix. The length of the alphaIIb transmembrane helix implies the absence of a significant transmembrane helix tilt in contrast to its partnering beta3 subunit. Sequence alignment shows Gly-991-Phe-993 to be fully conserved among all 18 human integrin alpha subunits, suggesting that their unusual structural motif is prototypical for integrin alpha subunits. The alphaIIb transmembrane structure demonstrates a level of complexity within the membrane that is beyond simple transmembrane helices and forms the structural basis for assessing the extent of structural and topological rearrangements upon alphaIIb-beta3 association, i.e. integrin transmembrane signaling.
Organizational Affiliation:
Department of Biochemistry and Molecular Biology and Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA.
