A functional role for VAP-33 in insulin-stimulated GLUT4 traffic.

摘要: Soluble N-ethylmaleimide sensitive factor attachment protein receptors (SNAREs) are critical proteins in membrane fusion, both regulated and constitutive vesicular traffic. In addition, that interact with the SNAREs thought to regulate fusion. Vesicle-associated protein-2 (VAMP-2) is a SNARE involved insulin-dependent glucose transporter 4 (GLUT4) VAMP-2 required for productive GLUT4 incorporation into plasma membrane. VAMP-associated of 33 kDa (VAP-33) an integral binds VAMPs vitro, hypothesized be regulator VAMPs. L6 skeletal myoblasts, which display traffic GLUT4, we show VAP-33 colocalized significantly using indirect confocal immunofluorescence biochemical cosegregation. Overexpression wild-type myoblasts attenuated myc-tagged membrane, this response was restored by co-overexpression linked green fluorescent protein. Antibodies microinjected 3T3-L1 adipocytes abrogated insulin-stimulated translocation as measured adhered lawns. Immunopurified VAMP-2-containing compartments from myotubes showed significant levels VAP-33. We propose may availability other vesicle fusion events.