Extracellular regulated kinase (ERK) interaction with actin and the calponin homology (CH) domain of actin-binding proteins

• Published in: Biochemical journal Vol. 344 Pt 1; no. 1; pp. 117 - 123
• Main Authors: Leinweber, B D, Leavis, P C, Grabarek, Z, Wang, C L, Morgan, K G
• Format: Journal Article
• Language: English
• Published: England 15.11.1999
• Subjects: Actinin - chemistry; Actinin - metabolism; Actins - metabolism; Animals; Binding Sites; Binding, Competitive; Calcium-Binding Proteins - chemistry; Calcium-Binding Proteins - metabolism; Calponins; In Vitro Techniques; Kinetics; Microfilament Proteins - chemistry; Microfilament Proteins - metabolism; Mitogen-Activated Protein Kinase 1 - metabolism; Mitogen-Activated Protein Kinase 3; Mitogen-Activated Protein Kinases - metabolism; Peptide Fragments - chemistry; Peptide Fragments - metabolism; Protein Binding; Protein Structure, Tertiary
• ISSN: 0264-6021; 1470-8728
• DOI: 10.1042/0264-6021:3440117

An interaction between extracellular regulated kinase 1 (ERK1) and calponin has previously been reported (Menice, Hulvershorn, Adam, Wang and Morgan (1997) J. Biol. Chem. 272 (40), 25157-25161) and has been suggested to reflect a function of calponin as a signalling molecule. We report in this study that calponin binds to both ERK1 and ERK2 under native conditions as well as in an overlay assay. Using chymotryptic fragments of calponin, the binding site of ERK on calponin was identified as the calponin homology (CH) domain, an N-terminal region of calponin found in other actin-binding proteins. ERK also bound, in a gel overlay assay, alpha-actinin, a protein with two tandem CH domains, as well as a 27 kDa thermolysin product of alpha-actinin containing the CH domains of alpha-actinin. The CH domain of calponin could compete with intact calponin or alpha-actinin for ERK binding. Titration of acrylodan-labelled calponin with ERK gave a K(a) of 6x10(6) M(-1) and titration of acrylodan-labelled calponin with a peptide from the alphaL16 helix of ERK gave a K(a) of 1x10(6) M(-1). Recombinant ERK was found to co-sediment with purified actin and induced a fluorescence change in pyrene-labelled F-actin (K(a)=5x10(6) M(-1)). The interaction of ERK with CH domains points to a new potential function for CH domains. The interaction of ERK with actin raises the possibility that actin may provide a scaffold for ERK signalling complexes in both muscle and non-muscle cells.