Kelch

Page updated 7th March '04

A protein first identified (Robinson et al, 1994) in the Drosophila mutant of the same name that have disorganised canal rings.  The protein has four domains.  From N to C, they are NTR N-terminal region responsible for the timing of the protein localization to the canal, the BTB region through which the protein self associates to form dimers, the IVR interveneing region required for localization, the KREP, kelch repeat domain consisting of six repeats .  Many other proteins contain kelch-like repeat, some of these have been shown to bind actin.  Scruin (Schmid et al, 1991) is the best characterised of the ABPs that bind actin through KREPs.  Drosophila Kelch binds actin through KREP number 5 (Kelso et al, 2002), and this actin binding is inhibited by phosphorylation of tyr 627 by src64 kinase.

Figure 1.  Organisation of Kelch proteins

A kelch-like protein KLEIP, in Madin-Darby Canine kidney cells is involved in the control of actin polymerization at cell-cell adhesion (Hara et al, 2004). KLEIP has the same overall arrangement as figure 1, with 6 kelch like repeats at the C-terminal half.

References:-

Hara, T., Ishida, H., Raziuddin, R., Dorkhom, S., Kamijo, K. & Miki, T. (2004) Novel Kelch-like Protein, KLEIP, Is Involved in Actin Assembly at Cell-Cell Contact Sites of Madin-Darby Canine Kidney Cells. Mol. Biol. Cell. 15, 1172-1184.

Kelso, R. J., Hudson, A. M. & Cooley, L. (2002) Drosophila kelch regulates actin organization via Src64-dependent tyrosine phosphorylation., J.Cell Biol. 156, 703-713.

Zhao, L., Gregoire, F. & Sul, H.S. (2000). "Transient induction of ENC-1, a kelch-related actin-binding protein, is required for adipocyte differentiation." J.Biol.Chem. 275(22), 16845-16850.