5DFRXXL region of long myosin light chain kinase causes F-actin bundle formation

Long myosin light chain kinase (L-MLCK) contains five DFRXXL motifs with ability to bind F-actin. Binding stoichiometry data indicated that each DFRXXL motif might bind each G-actin, but its biological significance remained unknown. We hypothesized that L-MLCK might act as an F-actin bundle peptides by its multiple binding sites of 5DFRXXL motifs to actin. In order to characterize F-actin-bundle formation properties of 5DFRXXL region of long myosin light chain kinase, we expressed and purified 5DFRXXL peptides tagged with HA in vitro. The properties of 5DFRXXL peptides binding to myofilaments or F-actin were analyzed by binding stoichiometries assays. The results indicated that 5DFRXXL peptides bound to myofilaments or F-actin with high affinity. KD values of 5DFRXXL binding to myofilaments and F-actin were 0.45 and 0.41 μmol/L, re- spectively. Cross-linking assay demonstrated that 5DFRXXL peptides could bundle F-actin efficiently. Typical F-actin bundles were observed morphologically through determina- tion of confocal and electron microscopy after adding 5DFRXXL peptides. After transfection of pEGFP-5DFRXXL plasmid into eukaryocyte, spike structure was observed around cell membrane edge. We guess that such structure formation may be attributable to F-actin over-bundle forma- tion caused by 5DFRXXL peptides. Therefore, we suppose that L-MLCK may be a new bundling protein and somehow play a certain role in organization of cell skeleton besides mediating cell contraction by it kinase activity.

作 者：   作者單位：   刊 名： 科學(xué)通報(bào)（英文版）  SCI 英文刊名： CHINESE SCIENCE BULLETIN  年，卷(期)： 2005 50(18)  分類號(hào)： Q5  關(guān)鍵詞： myosin light chain kinase   myofilament   actin   bundle protein  

【5DFRXXL region of long myosin light 】相關(guān)文章：

第212講：over the long haul / long shot05-04

Walk Light and Harmony05-04

Middle Region to Embrace Golden Time04-26

as long as you love me歌詞02-03

long shot風(fēng)險(xiǎn)大的賭注05-04

You Light Up My Life作文04-27

how long、how often 與 how soon04-27

第213講：short and sweet / the long ...05-04

第31講：green thumb; green light05-04

Flight Record Of Long March Series Of Launch Vehicles04-26