A Comprehensive Overview of the Vertebrate p24 Family: Identification of a Novel Tissue-Specifically Expressed Member

The members of the p24 protein family have an important but unclear role in transport processes in the early secretory pathway. The p24 family consists of four subfamilies (alpha, beta, gamma, and delta), whereby the exact composition of the family varies among species. Despite more than 15 years of p24 research, the vertebrate p24 family is still surprisingly ill characterized. Here, we describe the human, mouse, Xenopus, and zebrafish orthologues of 10 p24 family members and a new member that we term p24 gamma(5). Of these eleven p24 family members, nine are conserved throughout the vertebrate lineage, whereas two (p24 gamma(4) and p24 delta(2)) occur in some but not all vertebrates. We further show that all p24 proteins are widely expressed in mouse, except for p24 alpha(1) and p24 gamma(5) that display restricted expression patterns. Thus, we present for the first time a comprehensive overview of the phylogeny and expression of the vertebrate p24 protein family.