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 actinactivated ATPase activity (Vmax = 3.7 Pi s1 head1). The actin-sliding velocity of At myosin XI-I was 0.25 mm s1, >10 times lower than those of other class-XI myosins. The ADP dissociation rate from acto-At myosin XI-I was 17 s1, accounting for the low actin-sliding velocity. In contrast, the apparent affinity for actin in the presence of ATP, estimated from Kapp (0.61 mM) 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 mm s1) 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.
| Original language | English |
|---|---|
| Pages (from-to) | 1732-1743 |
| Number of pages | 12 |
| Journal | Plant and Cell Physiology |
| Volume | 57 |
| Issue number | 8 |
| DOIs | |
| Publication status | Published - 2016 Aug 1 |
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Keywords
- Actin
- Arabidopsis
- ATPase
- Kinetics
- Molecular motor
- Myosin
ASJC Scopus subject areas
- Medicine(all)
- Physiology
- Plant Science
- Cell Biology
Cite this
Myosin XI-I is mechanically and enzymatically unique among class-xi myosins in arabidopsis. / Haraguchi, Takeshi; Tominaga, Motoki; Nakano, Akihiko; Yamamoto, Keiichi; Ito, Kohji.
In: Plant and Cell Physiology, Vol. 57, No. 8, 01.08.2016, p. 1732-1743.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Myosin XI-I is mechanically and enzymatically unique among class-xi myosins in arabidopsis
AU - Haraguchi, Takeshi
AU - Tominaga, Motoki
AU - Nakano, Akihiko
AU - Yamamoto, Keiichi
AU - Ito, Kohji
PY - 2016/8/1
Y1 - 2016/8/1
N2 - 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 actinactivated ATPase activity (Vmax = 3.7 Pi s1 head1). The actin-sliding velocity of At myosin XI-I was 0.25 mm s1, >10 times lower than those of other class-XI myosins. The ADP dissociation rate from acto-At myosin XI-I was 17 s1, accounting for the low actin-sliding velocity. In contrast, the apparent affinity for actin in the presence of ATP, estimated from Kapp (0.61 mM) 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 mm s1) 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.
AB - 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 actinactivated ATPase activity (Vmax = 3.7 Pi s1 head1). The actin-sliding velocity of At myosin XI-I was 0.25 mm s1, >10 times lower than those of other class-XI myosins. The ADP dissociation rate from acto-At myosin XI-I was 17 s1, accounting for the low actin-sliding velocity. In contrast, the apparent affinity for actin in the presence of ATP, estimated from Kapp (0.61 mM) 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 mm s1) 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.
KW - Actin
KW - Arabidopsis
KW - ATPase
KW - Kinetics
KW - Molecular motor
KW - Myosin
UR - http://www.scopus.com/inward/record.url?scp=84988971321&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84988971321&partnerID=8YFLogxK
U2 - 10.1093/pcp/pcw097
DO - 10.1093/pcp/pcw097
M3 - Article
C2 - 27273580
AN - SCOPUS:84988971321
VL - 57
SP - 1732
EP - 1743
JO - Plant and Cell Physiology
JF - Plant and Cell Physiology
SN - 0032-0781
IS - 8
ER -