| Using a novel method to purify intracellular GLUT 4 enriched membranes , we identified by mass spectrometry the intermediate filament protein vimentin and the microtubule protein alpha tubulin as components of these membranes . ^^^ Disruption of intermediate filaments and microtubules in 3T3 L 1 adipocytes by microinjection of a vimentin derived peptide of the helix initiation 1A domain caused marked dispersion of perinuclear GLUT 4 to peripheral regions of the cells . ^^^ |