Analysis of the Rana catesbeiana tadpole tail fin proteome and phosphoproteome during T 3 -induced apoptosis: identification of a novel type I keratin
Date
2007-08-06
Authors
Domanski, Dominik
Helbing, Caren C.
Journal Title
Journal ISSN
Volume Title
Publisher
BioMed Central
Abstract
Background: Thyroid hormones (THs) are vital in the maintenance of homeostasis and in the
control of development. One postembryonic developmental process that is principally regulated
by THs is amphibian metamorphosis. This process has been intensively studied at the genomic level
yet very little information at the proteomic level exists. In addition, there is increasing evidence that
changes in the phosphoproteome influence TH action.
Results: Here we identify components of the proteome and phosphoproteome in the tail fin that
changed within 48 h of exposure of premetamorphic Rana catesbeiana tadpoles to 10 nM 3,5,3'-
triiodothyronine (T3). To this end, we developed a cell and protein fractionation method combined
with two-dimensional gel electrophoresis and phosphoprotein-specific staining. Altered proteins
were identified using mass spectrometry (MS). We identified and cloned a novel Rana larval type I
keratin, RLK I, which may be a target for caspase-mediated proteolysis upon exposure to T3. In
addition, the RLK I transcript is reduced during T3-induced and natural metamorphosis which is
consistent with a larval keratin. Furthermore, GILT, a protein involved in the immune system, is
changed in phosphorylation state which is linked to its activation. Using a complementary MS
technique for the analysis of differentially-expressed proteins, isobaric tags for relative and absolute
quantitation (iTRAQ) revealed 15 additional proteins whose levels were altered upon T3 treatment.
The success of identifying proteins whose levels changed upon T3 treatment with iTRAQ was
enhanced through de novo sequencing of MS data and homology database searching. These proteins
are involved in apoptosis, extracellular matrix structure, immune system, metabolism, mechanical
function, and oxygen transport.
Conclusion: We have demonstrated the ability to derive proteomics-based information from a
model species for postembryonic development for which no genome information is currently
available. The present study identifies proteins whose levels and/or phosphorylation states are
altered within 48 h of the induction of tadpole tail regression prior to overt remodeling of the tail.
In particular, we have identified a novel keratin that is a target for T3-mediated changes in the tail
that can serve as an indicator of early response to this hormone.
Description
BioMed Central
Keywords
Citation
Domanski and Helbing. Analysis of the Rana catesbeiana tadpole tail fin proteome and phosphoproteome during T 3 -induced apoptosis. BMC Developmental Biology 2007, 7 :94