Is Amoeba proteus Myosin VI Immunoanalogue a Dimeric Protein?

Magdalena Sobczak ； Maria Jolanta Redowicz

《Acta Protozoologica》 44卷4期 (2005/12) Pp. 389-394

並列摘要

Myosin Ⅵ is an unusual actin-based motor protein moving, unlike other known myosins, towards minus end of actin filaments. This implies a unique role of this protein in cell migration and intracellular transport. There are serious concerns whether myosin Ⅵ heavy chains may dimerize as its amino acid sequence contains heptad repeats responsible for dimerization but both native and recombinant myosins Ⅵ were found to be monomeric proteins. Recently, we have detected 130-kDa myosin Ⅵ immunoanalogue in Amoeba proteus that also exhibits many features characteristic for mammalian myosins Ⅵ (Dominik et al. 2005). It seemed interesting to check whether it is a monomeric or dimeric protein. Using a zero-length crosslinker, N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC), we have shown that under our experimental conditions the 130-kDa band corresponding to myosin Ⅵ immunoanalogue disappeared with the concomitant accumulation of about 260-kDa protein band. Similar results have been obtained when the coiled-coil skeletal muscle myosin rod was subjected to the EDC-crosslinking. These data indicate that the heavy chains of A. proteus myosin Ⅵ immunoanalogue may form dimers. These results also suggest that in vivo myosin Ⅵ immunoanalogue may play a role of an active transporter that requires dimerization and processivity.

並列關鍵字

Amoeba proteus ； crosslinking ； dimerization ； myosin Ⅵ immunoanalogue