2k1a
Bicelle-embedded integrin alpha(IIB) transmembrane segment
OverviewOverview
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.
About this StructureAbout this Structure
2K1A is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.
ReferenceReference
Structure of the Integrin {alpha}IIb Transmembrane Segment., Lau TL, Dua V, Ulmer TS, J Biol Chem. 2008 Jun 6;283(23):16162-8. Epub 2008 Apr 16. PMID:18417472 Page seeded by OCA on Wed Jun 18 12:16:12 2008