Receptor binding and biological activity of mammalian expressed sensory and motor neuron-derived factor (SMDF).
Sensory and motor neuron-derived factor (SMDF) is a member of the neuregulin family of proteins. SMDF is structurally characterized by a novel N-terminal domain. Using the signal sequence and N-terminal 28 amino acids (the "epitope") of herpes simplex virus type 1 glycoprotein D (gD), we have expressed SMDF as an epitope-tagged protein (gD-SMDF) in 293 cells, and purified it to > 98% homogeneity on a monoclonal anti-gD column. gD-SMDF stimulates human Schwann cell growth and 3H-thymidine incorporation in MCF-7 and T47D human breast tumor cells in vitro. The biological activity of gD-SMDF is consistent with its ability to compete with 125I-labeled heregulinbeta1 peptide (rHRGbeta1(177-244)) to bind to soluble dimeric ErbB receptor-IgG fusion proteins. gD-SMDF binds with low affinity to homodimeric ErbB3-IgG and ErbB4-IgG but with higher affinity to heterodimeric ErbB2/ErbB3-IgG and ErbB2/ErbB4-IgG. Using a SMDF-IgG(Fc) fusion protein we generated a monoclonal antibody (3G11) which binds SMDF, crossreacts with rHRGbeta1(177-244), and neutralizes the in vitro activities of gD-SMDF and rHRGbeta1(177-244) in human Schwann cells.
Osheroff
P L
PL
Department of Protein Chemistry, Genentech, Inc., South San Francisco, CA 94080, USA. plo@earthlink.net
Tsai
S P
SP
Chiang
N Y
NY
King
K L
KL
Li
R
R
Lewis
G D
GD
Wong
K
K
Henzel
W
W
Mather
J
J
D000818:Animals; D000911:Antibodies, Monoclonal; D001943:Breast Neoplasms / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism; D002455:Cell Division; D004305:Dose-Response Relationship, Drug; D066246:ErbB Receptors / Q000378:metabolism; D015870:Gene Expression; D006023:Glycoproteins / Q000378:metabolism; D006801:Humans; D007074:Immunoglobulin G / Q000378:metabolism; D007700:Kinetics; D009419:Nerve Tissue Proteins / Q000276:immunology / Q000378:metabolism*; D020890:Neuregulin-1; D011485:Protein Binding / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051381:Rats; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D020893:Receptor, ErbB-3; D066247:Receptor, ErbB-4; D011994:Recombinant Proteins / Q000378:metabolism; D012583:Schwann Cells / Q000378:metabolism
D000911:Antibodies, Monoclonal; D002352:Carrier Proteins; D066246:ErbB Receptors; D006023:Glycoproteins; D007074:Immunoglobulin G; D009419:Nerve Tissue Proteins; D020890:Neuregulin-1; D011518:Proto-Oncogene Proteins; D018719:Erb-b2 Receptor Tyrosine Kinases; D020893:Receptor, ErbB-3; D066247:Receptor, ErbB-4; D011994:Recombinant Proteins; C094131:NRG1 protein, human; C490580:Nrg1 protein, rat; C092262:heregulin beta 1 (177-244); C587689:ERBB4 protein, human; C587691:Erbb4 protein, rat