Protein Information

General Information
MoonProt ID133
First appeared in release1.0
Name(s)Thymosin beta-4 T beta-4 TB4X THYB4 TMSB4 Gene Name: TMSB4X
UniProt IDP62328 (TYB4_HUMAN), Reviewed
GO termsGO:0002576 platelet degranulation GO:0007010 cytoskeleton organization GO:0007596 blood coagulation GO:0030036 actin cytoskeleton organization GO:0030168 platelet activation GO:0042989 sequestering of actin monomers GO:0003779 actin binding GO:0005515 protein binding GO:0044822 poly(A) RNA binding GO:0005576 extracellular region GO:0005737 cytoplasm GO:0005856 cytoskeleton GO:0031093 platelet alpha granule lumen GO:0050728 negative regulation of inflammatory response GO:0050728 negative regulation of inflammatory
Organisms for which functions have been demonstratedHomo sapiens (Human)
Sequence length44
FASTA sequence>gi|11056061|ref|NP_066932.1| thymosin beta-4 [Homo sapiens] MSDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES
Structure Information
PDB ID3TU5
Quaternary structure
Function 1
Function descriptionInvolved in sequestering G-actin (monomeric actin) in human polymorphonuclear leukocytes (PMNs).
References for functionD Safer, M Elzinga, and V T Nachmias. Thymosin beta 4 and Fx, an actin-sequestering peptide, are indistinguishable. J. Biol. Chem. 1991 266: 4029-32. Cassimeris, L., Safer, D., Nachmias, V.T. & Zigmond, S.H. Thymosin ?4 sequesters the majority of G-actin in resting human polymorphonuclear leukocytes. J. Cell Biol. 119, 12611270 (1992).
E.C. numberN/A
Location of functional site(s)
Cellular location of functioncytoplasm
Comments"Thymosin B4 appears to be an intrinsically disordered protein that binds to actin. Modeling and Cross-linking studies suggest that TB4 binds to actin at locations: Lys3, Lys18, Lys38. However, a high percentage of residues still do participate in functional interactions between the two macromolecules." From: Safer, D. et al . 1997. Thymosin beta 4 binds actin in an extended conformation and contacts both the barbed and pointed ends. Biochemistry 36: 58065816. Thymosin B4 forms a 1:1 complex with G-actin and inhibits its polymerization. PDB #1T44 contains a fragment of Thymosin B4.
Function 2
Function descriptionsecreted anti-inflammatory agent
References for functionYoung JD, Lawrence AJ, MacLean AG, Leung BP, McInnes IB, Canas B, Pappin DJ, Stevenson RD. Thymosin beta 4 sulfoxide is an anti-inflammatory agent generated by monocytes in the presence of glucocorticoids. Nat Med. 1999 Dec. PMID: 10581087
E.C. numberN/A
Location of functional site(s)
Cellular location of functionExtracellular. Secreted protein.
Comments"Met-6 is thought to play an important role in the signaling process." Young JD, Lawrence AJ, MacLean AG, Leung BP, McInnes IB, Canas B, Pappin DJ, Stevenson RD. Nat Med. 1999 Dec;5(12):1424-7. PMID: 10581087 "Thymosin B4 is generated by monocytes in the presence of glococorticoids and inhibits anti-inflammatory response. Thymosin B4 sulfoxide is formed by the oxidation of Methionine 6 (Met-6), and appears to be the active form in inhibiting inflammation."