The role of a conserved membrane proximal cysteine in altering ?PS2C?PS integrin diffusion.

ABSTRACT: Cysteine residues (Cys) in the membrane proximal region are common post-translational modification (PTM) sites in transmembrane proteins. Herein, the effects of a highly conserved membrane proximal ?-subunit Cys1368 on the diffusion properties of ?PS2C?PS integrins are reported. Sequence alignment shows that this cysteine is palmitoylated in human ?3 and ?6 integrin subunits. Replacing Cys1368 in wild-type integrins with valine (Val1368) putatively blocks a PTM site and alters integrins' ligand binding and diffusion characteristics. Both fluorescence recovery after photobleaching (FRAP) and single particle tracking (SPT) diffusion measurements show Val1368 integrins are more mobile compared to wild-type integrins. Approximately 33% and 8% more Val1368 integrins are mobile as measured by FRAP and SPT, respectively. The mobile Val1368 integrins also exhibit less time-dependent diffusion, as measured by FRAP. Tandem mass spectrometry data suggest that Cys1368 contains a redox or palmitoylation PTM in ?PS2C?PS integrins. This membrane proximal Cys may play an important role in the diffusion of other alpha subunits that contain this conserved residue.

SUBMITTER: Syed A 

PROVIDER: S-EPMC5155636 | biostudies-literature | 2016 Nov

REPOSITORIES: biostudies-literature