A membrane-bound vertebrate globin
- Authors
- Blank, M., Wollberg, J., Gerlach, F., Reimann, K., Roesner, A., Hankeln, T., Fago, A., Weber, R.E., and Burmester, T.
- ID
- ZDB-PUB-111012-1
- Date
- 2011
- Source
- PLoS One 6(9): e25292 (Journal)
- Registered Authors
- Keywords
- Globins, Zebrafish, Cell membranes, Vertebrates, Heme, Eyes, Myristoylation, Recombinant proteins
- MeSH Terms
-
- Amino Acid Sequence
- Animals
- Cell Membrane/metabolism*
- Gene Expression Regulation, Developmental
- Globins/genetics
- Globins/immunology
- Globins/metabolism*
- Green Fluorescent Proteins/genetics
- Green Fluorescent Proteins/metabolism
- Heme/metabolism
- Immunoglobulin G/immunology
- Immunoglobulin G/metabolism
- Lipoylation
- Molecular Sequence Data
- Oxygen/metabolism*
- Rabbits
- Recombinant Proteins/genetics
- Recombinant Proteins/isolation & purification
- Recombinant Proteins/metabolism*
- Sequence Homology, Amino Acid
- Subcellular Fractions
- Zebrafish/physiology*
- PubMed
- 21949889 Full text @ PLoS One
The family of vertebrate globins includes hemoglobin, myoglobin, and other O2-binding proteins of yet unclear functions. Among these, globin X is restricted to fish and amphibians. Zebrafish (Danio rerio) globin X is expressed at low levels in neurons of the central nervous system and appears to be associated with the sensory system. The protein harbors a unique N-terminal extension with putative N-myristoylation and S-palmitoylation sites, suggesting membrane-association. Intracellular localization and transport of globin X was studied in 3T3 cells employing green fluorescence protein fusion constructs. Both myristoylation and palmitoylation sites are required for correct targeting and membrane localization of globin X. To the best of our knowledge, this is the first time that a vertebrate globin has been identified as component of the cell membrane. Globin X has a hexacoordinate binding scheme and displays cooperative O2 binding with a variable affinity (P50~1.3–12.5 torr), depending on buffer conditions. A respiratory function of globin X is unlikely, but analogous to some prokaryotic membrane-globins it may either protect the lipids in cell membrane from oxidation or may act as a redox-sensing or signaling protein.