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- ************************************************
- * Interleukin-6 / G-CSF / MGF family signature *
- ************************************************
-
- The following cytokines can be grouped into a single family on the basis of
- sequence similarities.
-
- - Interleukin-6 (IL-6) [1] (also known as B-cell stimulatory factor 2 (BSF-2)
- or interferon beta-2) is a cytokine that has a wide variety of biological
- functions. It plays an essential role in the final differentiation of B-
- cells into IG-secreting cells, as well as inducing myeloma/plasmacytoma
- growth, nerve cell differentiation and, in hepatocytes, acute phase
- reactants.
- - Granulocyte colony-stimulating factor (G-CSF) [2] belongs to the cytokine
- family whose members regulate hematopoietic cell proliferation and
- differentiation. G-CSF exclusively stimulates the colony formation of
- granulocytes.
- - Myelomonocytic growth factor (MGF) [3] is an avian hematopoeitic growth
- factor that stimulates the proliferation and colony formation of normal and
- transformed avian cells of the myeloid lineage.
-
- These cytokines are glycoproteins of about 170 to 180 amino acid residues that
- contains four conserved cysteine residues involved in two disulfide bonds [4],
- as shown in the following schematic representation.
-
- +--+ +---+
- | | | |
- xxxxxxxxxxxCxxCxxxxxCxxxCxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
- **********
-
- 'C': conserved cysteine involved in a disulfide bond.
- '*': position of the pattern.
-
- The pattern developed for this family of proteins includes the last two
- cysteines as well as other conserved residues.
-
- -Consensus pattern: C-x(9)-C-x(6)-G-L-x(2)-[FY]-x(3)-L
- [The two C's are involved in disulfide bonds]
- -Sequences known to belong to this class detected by the pattern: ALL.
- -Other sequence(s) detected in SWISS-PROT: NONE.
-
- -Note: it has been said [5] that this family can be extended by the adjunction
- of LIF and OSM (see the relevant section) but, while all these cytokines seem
- to be structurally related, the sequence similarity is not high enough to
- allow the use of only one single consensus pattern.
-
- -Last update: June 1994 / Text revised.
-
- [ 1] Kishimoto T., Hirano T.
- BioEssays 9:11-15(1988).
- [ 2] Metcalf D.
- Science 229:16-22(1985).
- [ 3] Leutz A., Damm K., Sterneck E., Kowenz E., Ness S., Frank R.,
- Gausepohl H., Pan Y.-C.E., Smart J., Hayman M., Graf T.
- EMBO J. 8:175-181(1989).
- [ 4] Clogston C.L., Boone T.C., Crandall B.C., Mendiaz E.A., Lu H.S.
- Arch. Biochem. Biophys. 272:144-151(1989).
- [ 5] Rose T.M., Bruce A.G.
- Proc. Natl. Acad. Sci. U.S.A. 88:8641-8645(1991).
-