分子内結合が調節するJRABのLIMドメインによるアクチン細胞骨格の再編成

JRAB/MICAL-L2 is an effector protein of Rab13, a member of the Rab family of small GTPase. JRAB/MICAL-L2 consists of a calponin homology domain, a LIM domain, and a coiled-coil domain. JRAB/MICAL-L2 engages in intramolecular interaction between the N-terminal LIM domain and the C-terminal coiled-coil domain, and changes its conformation from closed to open under the effect of Rab13. Open-form JRAB/MICAL-L2 induces the formation of peripheral ruffles via an interaction between its calponin homology domain and filamin. Here, we report that the LIM domain, independent of the C-terminus, is also necessary for the function of open-form JRAB/MICAL-L2. In mechanistic terms, two zinc finger domains within the LIM domain bind the first and second molecules of actin at the minus end, potentially inhibiting the depolymerization of actin filaments (F-actin). The first zinc finger domain also contributes to the intramolecular interaction of JRAB/MICAL-L2. Moreover, the residues of the first zinc finger domain that are responsible for the intramolecular interaction are also involved in the association with F-actin. Together, our findings show that the function of open-form JRAB/MICAL-L2 mediated by the LIM domain is fine-tuned by the intramolecular interaction between the first zinc finger domain and the C-terminal domain

Insights into Land Plant Evolution Garnered from the Marchantia polymorpha Genome.

The evolution of land flora transformed the terrestrial environment. Land plants evolved from an ancestral charophycean alga from which they inherited developmental, biochemical, and cell biological attributes. Additional biochemical and physiological adaptations to land, and a life cycle with an alternation between multicellular haploid and diploid generations that facilitated efficient dispersal of desiccation tolerant spores, evolved in the ancestral land plant. We analyzed the genome of the liverwort Marchantia polymorpha, a member of a basal land plant lineage. Relative to charophycean algae, land plant genomes are characterized by genes encoding novel biochemical pathways, new phytohormone signaling pathways (notably auxin), expanded repertoires of signaling pathways, and increased diversity in some transcription factor families. Compared with other sequenced land plants, M. polymorpha exhibits low genetic redundancy in most regulatory pathways, with this portion of its genome resembling that predicted for the ancestral land plant. PAPERCLIP

ショクサイ チョクゴ ノ シタガリ ガ ヒノキ ジンコウ ゾウリンチ ニ シンニュウ シタ コウヨウジュ ノ ソセイ セイチョウ オヨビ マイド シュシ ニ オヨボス エイキョウ

To evaluate the effect of the weeding and the salvage cutting on the vegetation structure of artificial stand, the vegetation and the seed bank were investigated on 12 year old Chamaecyparis obtuse stand of the experimental forest of Gifu University. At the time planting, a part of plantation with the area of about 400m2 (non-weeding plot) was leaved intacted and during 12 years no practice had been conducted in the non-weeding plot. Two sample sites were selected for the non-weeding site, the weeding site, the edge of natural stand, and the natural stand. In each sample site, 3 to 6 soil blocks (2000cm3) were samples and used for the germination experiment in the green house. For the non-weeding site and the weeding site, species, DBH, and height were recorded for all trees with height over 2m in 5m×5m quadrat. ..