Membrane-anchored growth factors, the epidermal growth factor family: beyond receptor ligands.
The epidermal growth factor (EGF) family and the EGF receptor (EGFR, ErbB) tyrosine kinase family have been spearheading the studies of signal transduction events that determine cell fate and behavior in vitro and in vivo. The EGFR family and their signaling pathways are giving us tremendous advantages in developing fascinating molecular target strategies for cancer therapy. Currently, two important types of EGFR inhibitors are in clinical use: neutralizing antibodies of EGFR or ErbB2, and synthetic small compounds of tyrosine kinase inhibitors designed for receptors. On the other hand, basic research of the EGF family ligands presents new challenges as membrane-anchored growth factors. All members of the EGF family have important roles in development and diseases and are shed from the plasma membrane by metalloproteases. The ectodomain shedding of the ligands has emerged as a critical component in the functional transactivation of EGFRs in interreceptor cross-talk in response to various shedding stimulants such as G-protein coupled receptor agonists, growth factors, cytokines, and various physicochemical stresses. Among the EGFR-ligands, heparin-binding EGF-like growth factor (HB-EGF) is a prominent ligand in our understanding of the pathophysiological roles of ectodomain shedding in cancer, wound healing, cardiac diseases, etc. Here we focus on ectodomain shedding of the EGF family ligands, especially HB-EGF by disintegrin and metalloproteases, which are not only key events of receptor cross talk, but also novel intercellular signaling by their carboxy-terminal fragments to regulate gene expression directly.
Higashiyama
Shigeki
S
Department of Biochemistry and Molecular Genetics, Center for Regenerative Medicine (CEREM), Ehime University Graduate School of Medicine, Shitsukawa, Toon, Ehime 791-0295, Japan. shigeki@m.ehime-u.ac.jp
Iwabuki
Hidehiko
H
Morimoto
Chie
C
Hieda
Miki
M
Inoue
Hirofumi
H
Matsushita
Natsuki
N
D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D019483:Disintegrins / Q000378:metabolism; D004815:Epidermal Growth Factor / Q000378:metabolism*; D066246:ErbB Receptors / Q000378:metabolism*; D066257:Heparin-binding EGF-like Growth Factor; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism; D008024:Ligands; D008566:Membranes / Q000378:metabolism; D045726:Metalloproteases / Q000378:metabolism; D008954:Models, Biological; D009369:Neoplasms / Q000378:metabolism; D015398:Signal Transduction; D015533:Transcriptional Activation / Q000502:physiology
D019483:Disintegrins; C587883:HBEGF protein, human; D066257:Heparin-binding EGF-like Growth Factor; D036341:Intercellular Signaling Peptides and Proteins; D008024:Ligands; D004815:Epidermal Growth Factor; D066246:ErbB Receptors; D045726:Metalloproteases