| Literature References | 1. YOKOTA, T., ARAI, N., LEE, F., RENNICK, D., MOSMANN, T. AND ARAI, K.
Use of a cDNA expression vector for isolation of mouse interleukin-2 cDNA
clones - expression of T-cell growth factor activity after transfection of
monkey cells.
PROC.NATL.ACAD.SCI.U.S.A. 82(1) 68-72 (1985).
2. CERRETTI, D.P., MCKEREGHAN, K., LARSEN, A., CANTRELL, M.A., ANDERSON, D.,
GILLIS, S., COSMAN, D. AND BAKER, P.E.
Cloning, sequence, and expression of bovine interleukin 2
PROC.NATL.ACAD.SCI.U.S.A. 83(10) 3223-3227 (1986).
3. MOTT, H.R., DRISCOLL, P.C., BOYD, J., COOKE, R.M., WEIR, M.P. AND
CAMPBELL, I.D.
Secondary structure of human interleukin 2 from 3D heteronuclear NMR
experiments.
BIOCHEMISTRY 31(33) 7741-7744 (1992).
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| Documentation | T-Lymphocytes regulate the growth and differentiation of certain lympho-
poietic and haemopoietic cells through the release of various secreted
protein factors [1]. These factors, which include interleukin-2 (IL2), are
secreted by lectin- or antigen-stimulated T-cells, and have various
physiological effects. IL2 is a lymphokine that induces the proliferation
of responsive T-cells. In addition, it acts on some B-cells, via receptor-
specific binding [2], as a growth factor and antibody production stimulant
[3]. The protein is secreted as a single glycosylated polypeptide, cleavage
of a signal sequence being required for its activity, which is partially
species restricted [2].
Solution NMR suggests that IL2 is a mainly alpha-helical protein, its
structure comprising a bundle of 4 helices (termed A-D), flanked by 2
shorter helices and several poorly-defined loops. Residues in helix A, and
in the loop region between helices A and B, are important for receptor
binding [3]. Secondary structure analysis has suggested similarity to IL4
and granulocyte-macrophage colony stimulating factor (GMCSF) [3].
INTERLEUKIN2 is a 5-element fingerprint that provides a signature for the
IL2 cytokine family. The fingerprint was derived from an initial alignment
of 4 sequences: motif 1 spans the signal peptide and the highly-conserved
N-terminal PTSSST sequence; motif 3 includes the region encoded by PROSITE
pattern INTERLEUKIN_2 (PS00424); and motifs 3 and 4 each contain a Cys
residue required to form a disulphide bridge that stabilises the active
form of the peptide. Two iterations on OWL22.1 were required to reach
convergence, at which point a true set comprising 11 sequences was
identified. Five partial matches were also found: S34052, SYNDABILA,
SYNDABILB and SYNDABILC are IL2 sequences and fusion proteins that lack
the signal peptide; and S31209 is an IL2 fusion protein fragment.
An update on SPTR37_9f identified a true set of 19 sequences.
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