0000000000013045
AUTHOR
Christian Hunzinger
Evolution of tissue-specific keratins as deduced from novel cDNA sequences of the lungfish Protopterus aethiopicus.
Lungfishes are possibly the closest extant relatives of the land vertebrates (tetrapods). We report here the cDNA and predicted amino acid sequences of 13 different keratins (ten type I and three type II) of the lungfish Protopterus aethiopicus. These keratins include the orthologs of human K8 and K18. The lungfish keratins were also identified in tissue extracts using two-dimensional polyacrylamide gel electrophoresis, keratin blot binding assays and immunoblotting. The identified keratin spots were analyzed by peptide mass fingerprinting which assigned seven sequences (inclusively Protopterus K8 and K18) to their respective protein spot. The peptide mass fingerprints also revealed the fac…
A novel and ancient group of type I keratins with members in bichir, sturgeon and gar
Abstract 1. Background Vertebrate epithelial cells typically express a specific set of keratins. In teleosts, keratins are also present in a variety of mesenchymal cells, which usually express vimentin. Significantly, our previous studies revealed that virtually all known teleost keratins evolved independently from those present in terrestrial vertebrates. To further elucidate the evolutionary scenario that led to the large variety of keratins and their complex expression patterns in present day teleosts, we have investigated their presence in bichir, sturgeon and gar. 2. Results We have discovered a novel group of type I keratins with members in all three of these ancient ray-finned fish, …
Integrative proteomics: functional and molecular characterization of a particular glutamate-related neuregulin isoform.
Glutamate is the major excitatory neurotransmitter in the mammalian brain and is related to memory by calcium-conducting receptors. Neuregulins have emerged as long-term modulating molecules of synaptic signaling by glutamate receptors, playing a role in some cognition/memory-related disorders and moreover being part of transient functional microdomains, called lipid rafts. Here we characterize one specific isoform of neuregulin as a central biomarker for glutamate-related signaling, integrating results from in vitro and in vivo models by a differential functional and proteomic approach.
cDNA sequences of the authentic keratins 8 and 18 in zebrafish
From the zebrafish Danio rerio, we have cDNA cloned and sequenced a novel type II and a novel type I keratin, termed DreK8 and DreK18, respectively. We identified DreK8/18 as the true orthologs of the human keratin pair K8/18 as follows: (i) MALDI-MS assignment to the biochemically identified K8 and K18 candidates that are co-expressed in simple epithelia and absent in epidermal keratinocytes; (ii) multiple sequence alignments and phylogenetic tree analysis, showing that DreK8, within the phylogenetic tree of type II keratins, forms a highly bootstrap-supported branch together with K8 from goldfish and rainbow trout, whereas DreK18, within the phylogenetic tree of type I keratins, groups wi…