Differential Control of ErbB2 Surface Expression in Breast Cancer Cells by an Alternatively Spliced Form of ERBIN
Annual summary rept. 1 May 2002-30 Apr 2003
GEORGETOWN UNIV WASHINGTON DC
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Receptor internalization following ligand stimulation is an important way of attenuating downstream signaling. One such family of proteins involved in this process are the Vps proteins. Vps proteins are a family of proteins first identified in Yeast that are required for proper vacuolar protein sorting hence the name Vps. Yeast Snf7p is a small coiled-coiled protein involved in multivesicular body MVB function. Genomic and proteonomic studies indicate yeast Snf7p also interacts with Bro1-containing proteins, Bro1p and Rim20p, involved in MVB function and pH signal transduction, respectively. Here we report the identification of Snf7-1, one of a family of at least three human homologs of yeast Snf7p. Using affinity-capture experiments, we show that human Snf7-1 interacts with AIP1, a mammalian Bro1p-containing protein involved in apoptosis and cellular vacuolization. Snf7-1 did not, however, interact with another human Bro1-containing molecule, Rhophilin-2. Additional domain mapping using affinity-capture experiments revealed that the N-terminus of AIP1 was necessary and sufficient for interacting with Snf7-1. These results suggest the possibility that the Snf7-1-AIP1 interaction plays a role in mammalian MVB function.
- Medicine and Medical Research