RRC ID 52820
著者 Haraguchi T, Tominaga M, Nakano A, Yamamoto K, Ito K.
タイトル Myosin XI-I is Mechanically and Enzymatically Unique Among Class-XI Myosins in Arabidopsis.
ジャーナル Plant Cell Physiol
Abstract Arabidopsis possesses 13 genes encoding class-XI myosins. Among these, myosin XI-I is phylogenetically distant. To examine the molecular properties of Arabidopsis thaliana myosin XI-I (At myosin XI-I), we performed in vitro mechanical and enzymatic analyses using recombinant constructs of At myosin XI-I. Unlike other biochemically studied class-XI myosins, At myosin XI-I showed extremely low actin-activated ATPase activity (Vmax = 3.7 Pi s(-1) head(-1)). The actin-sliding velocity of At myosin XI-I was 0.25 µm s(-1), >10 times lower than those of other class-XI myosins. The ADP dissociation rate from acto-At myosin XI-I was 17 s(-1), accounting for the low actin-sliding velocity. In contrast, the apparent affinity for actin in the presence of ATP, estimated from Kapp (0.61 µM) of actin-activated ATPase, was extremely high. The equilibrium dissociation constant for actin was very low in both the presence and absence of ATP, indicating a high affinity for actin. To examine At myosin XI-I motility in vivo, green fluorescent protein-fused full-length At myosin XI-I was expressed in cultured Arabidopsis cells. At myosin XI-I localized not only on the nuclear envelope but also on small dots moving slowly (0.23 µm s(-1)) along actin filaments. Our results show that the properties of At myosin XI-I differ from those of other Arabidopsis class-XI myosins. The data suggest that At myosin XI-I does not function as a driving force for cytoplasmic streaming but regulates the organelle velocity, supports processive organelle movement or acts as a tension generator.
巻・号 57(8)
ページ 1732-43
公開日 2016-8-1
DOI 10.1093/pcp/pcw097
PII pcw097
PMID 27273580
MeSH Actin Cytoskeleton / metabolism Actins / metabolism Adenosine Triphosphate / metabolism Arabidopsis / cytology Arabidopsis / enzymology* Arabidopsis / genetics Arabidopsis Proteins / genetics Arabidopsis Proteins / metabolism* Cell Nucleus / metabolism Cytoplasmic Streaming Genes, Reporter Molecular Motor Proteins / genetics Molecular Motor Proteins / metabolism* Organelles / metabolism Protein Transport
IF 4.062
引用数 9
リソース情報
シロイヌナズナ / 植物培養細胞・遺伝子 pda19579