Cloning of the YAP19 gene encoding a putative yeast homolog of AP19, the mammalian small chain of the clathrin-assembly proteins.

Mouse brain AP19 is the smallest polypeptide chain component of AP-1, the clathrin-assembly protein complex located at the Golgi complex. We isolated a gene, termed YAP19, potentially encoding a homolog of AP19 from the genomic DNA of the yeast Saccharomyces cerevisiae. The deduced amino acid sequence, 156 amino acids long, shows 53% identity with the mouse brain AP19 protein, but 37% with Yap17p, a yeast homolog of the mammalian AP17 in AP-2, another clathrin-assembly protein complex located at the plasma membrane. The identification of YAP19 supports the proposal that yeast cells also contain the Golgi-associated clathrin-assembly protein complex.