A novel β-thymosin from the sea urchin: extending the phylogenetic distribution of β-thymosins from mammals to echinoderms

Abstract

The study of the phylogenetic distribution of the beta-thymosin family is important to elucidate its biological function further. A new thymosin, designated as thymosin beta 14, consisting of 40 amino acid residues and with a molecular weight of 4537 Da as determined by ion spray mass spectrometry, was isolated from the sea urchin. The N-terminus of this polypeptide is blocked by an acetyl group as found by matrix-assisted laser desorption mass spectrometric and amino acid analysis. The primary structure was elucidate by Edman degradation of the HPLC-purified thymosin beta 14 fragments produced by digestion with endoproteinase Asp-N and trypsin. Sequence comparison reveals that thymosin beta 14 is 73% homologous to thymosin beta 4, obtained from calf thymus. By isolating and characterising the structure of thymosin beta 14 from the sea urchin, an invertebrate, substantial knowledge about the phylogenetic distribution and evolution of beta-thymosins is gained.

Identification and characterization of homologues of vertebrate β‐thymosin in the marine mollusk Aplysia californica

“…Larger ions corresponding to truncated forms of ApβTs were not observed either. Among invertebrates, the acetylation of β‐thymosin protein at the N ‐terminus was confirmed by MALDI MS in sea urchin35 and sea scallop 34. Our results illustrated the advantage of using an MS approach that allowed us not only to determine the posttranslational modification on the apβT His protein, as predicted by molecular biology methods, but also to find a closely related protein, apβT Gln .…”

“…The β‐thymosin proteins have been characterized in many vertebrates, including humans,8, 33 and invertebrates such as echinoderms34, 35 and mollusks 34. Input of the full apβT His and apβT Gln sequences into an NCBI BLAST database search returned 148 and 154 hits, respectively.…”

“…Most of the homologues of apβT proteins retrieved from public databases are currently characterized at the nucleotide or gene level. We found a number of published reports on the molecular characterization of β‐thymosin from various species, including human,32 rat,36 sea urchin35 and sea scallop 34. A few of the highest‐ranked sequences are compared in Fig.…”

“… Sequence alignments of two novel Aplysia β‐thymosin isoforms and related thymosin proteins from different species (GenPept sea urchin, AAC26833; rainbow trout, P26352; perch, AAB21004; and chick, AAQ55552.1); confirmed acetylated residues are indicated 35, 37, 38. Translated sequence of the chick β 4 thymosin contains priming methionine.…”

One-TrialIn VitroConditioning Regulates a Cytoskeletal-Related Protein (CSP24) in the Conditioned Stimulus Pathway ofHermissenda

“…One of the proteins designated as CSP24 (cytoskeletal-related protein 24), is a 24 kDa apparent molecular weight phosphoprotein that is associated with intermediate memory, distinct from short-term memory, produced by one-trial conditioning (Crow and Xue-Bian, 2000). Amino acid sequences of peptides derived from CSP24 exhibited varying degrees of sequence identity to the ␤-thymosin family of actin-binding proteins (Nachmias, 1993;Carpintero et al, 1995;Safer and Chowrashi, 1997;Stoeva et al, 1997) and of actin-binding proteins consisting of multiple ␤-thymosin repeats (Hertzog et al, 2002). Here we show the distribution of CSP24 immunoreactivity in sections of the circumesophageal nervous system using anti-CSP24 antibody.…”