RESUMEN

We have identified a 102 kDa protein, p102, which is found on the cytoplasmic face of Golgi membranes, exocytic transport vesicles and in the cytosol. A monoclonal antibody that cross-reacts with p102 is able to immunoprecipitate a 500-600 kDa protein complex containing p102 and additional subunits. The composition of this p102-containing protein complex resembles that of the Golgi coatomer complex, which constitutes the coat of non-clathrin coated vesicles. One of the subunits of the p102 complex reacts with a monoclonal antibody that detects beta-COP, a subunit of the Golgi coatomer complex. Like beta-COP, p102 exists in a brefeldin A-sensitive association with Golgi membranes. The sequence of p102 contains an N-terminal domain composed of six repeats which are similar to those found in the beta subunit of trimeric G proteins and other regulatory proteins. We suggest that p102 may be involved in regulating membrane traffic in the constitutive exocytic pathway.

Asunto(s)

Proteínas de Unión al GTP/química , Aparato de Golgi/química , Proteínas de la Membrana/química , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales/inmunología , Western Blotting , Brefeldino A , Clonación Molecular , Proteína Coatómero , Reacciones Cruzadas , Ciclopentanos/farmacología , ADN , Células HeLa , Humanos , Membranas Intracelulares/química , Proteínas de la Membrana/inmunología , Ratones , Datos de Secuencia Molecular , Homología de Secuencia de Aminoácido , Transducina/química