Phosphorylation and dephosphorylation of Ser852 and Ser889 control the clustering, localization and function of PAR3.

Cell polarity is essential for various asymmetric cellular events, and the partitioning defective (PAR) protein PAR3 (encoded by in mammals) plays a unique role as a cellular landmark to establish polarity. In epithelial cells, PAR3 localizes at the subapical border, such as the tight junction in vertebrates, and functions as an apical determinant. Although we know a great deal about the regulators of PAR3 localization, how PAR3 is concentrated and localized to a specific membrane domain remains an important question to be clarified.

MTCL1 crosslinks and stabilizes non-centrosomal microtubules on the Golgi membrane.

Recent studies have revealed the presence of a microtubule subpopulation called Golgi-derived microtubules that support Golgi ribbon formation, which is required for maintaining polarized cell migration. CLASPs and AKAP450/CG-NAP are involved in their formation, but the underlying molecular mechanisms remain unclear. Here, we find that the microtubule-crosslinking protein, MTCL1, is recruited to the Golgi membranes through interactions with CLASPs and AKAP450/CG-NAP, and promotes microtubule growth from the Golgi membrane.

The novel PAR-1-binding protein MTCL1 has crucial roles in organizing microtubules in polarizing epithelial cells.

The establishment of epithelial polarity is tightly linked to the dramatic reorganization of microtubules (MTs) from a radial array to a vertical alignment of non-centrosomal MT bundles along the lateral membrane, and a meshwork under the apical and basal membranes. However, little is known about the underlying molecular mechanism of this polarity-dependent MT remodeling. The evolutionarily conserved cell polarity-regulating kinase PAR-1 (known as MARK in mammals), whose activity is essential for maintaining the dynamic state of MTs, has indispensable roles in promoting this process.

Development of a novel emergency hemostatic kit for severe hemorrhage.

Photocrosslinkable chitosan (Az-CH-LA) contains lactose moieties and photoreactive azide groups, and its viscous solution forms an insoluble hydrogel on exposure to UV irradiation. We previously developed an emergency hemostatic kit using the Az-CH-LA solution, calcium alginate, and a UV irradiation apparatus. However, a suitable UV irradiation apparatus is required to effectively convert the Az-CH-LA solution into a hydrogel, and power supply to use the UV irradiation apparatus may not always be available in a disaster area or battlefield.

Angiogenesis following cell injection is induced by an excess inflammatory response coordinated by bone marrow cells.

The aim of this study was to identify novel angiogenic mechanisms underlying the regenerative process. To that end, interactions between adipose tissue-derived stromal cells (ASCs) and bone marrow cells (BMCs) were initially investigated using real-time fluorescence optical imaging. To monitor cell behavior in mice, we injected green fluorescent protein-positive (GFP(+)) BMCs into the tail vein and injected PKH26-labeled ASCs behind the ears.

The 8th and 9th tandem spectrin-like repeats of utrophin cooperatively form a functional unit to interact with polarity-regulating kinase PAR-1b.

Utrophin is a widely expressed paralogue of dystrophin, the protein responsible for Duchenne muscular dystrophy. Utrophin is a large spectrin-like protein whose C-terminal domain mediates anchorage to a laminin receptor, dystroglycan (DG). The rod domain, composed of 22 spectrin-like repeats, connects the N-terminal actin-binding domain and the C-terminal DG binding domain, and thus mediates molecular linkage between intracellular F-actin and extracellular basement membrane.

Intracellular polarity protein PAR-1 regulates extracellular laminin assembly by regulating the dystroglycan complex.

Cell polarity depends on extrinsic spatial cues and intrinsic polarity proteins including PAR-aPKC proteins. In mammalian epithelial cells, cell-cell contacts provide spatial cues that activate the aPKC-PAR-3-PAR-6 complex to establish the landmark of the initial cellular asymmetry. PAR-1, a downstream target of the aPKC-PAR-3-PAR-6 complex, mediates further development of the apical and basolateral membrane domains.

Expansion and characterization of human bone marrow-derived mesenchymal stem cells cultured on fragmin/protamine microparticle-coated matrix with fibroblast growth factor-2 in low serum medium.

Fragmin/protamine microparticles (F/P MPs) can be stably coated onto plastic surfaces. A capability of F/P MP-coated plates was investigated to immobilize fibroblast growth factor (FGF)-2 as a substratum to expand human bone marrow-derived mesenchymal stem cells (BMMSCs). FGF-2 molecules in low (2%) human serum (HS) medium were immobilized onto F/P MP-coated plates, and the FGF-2 was gradually released into the medium with a half-releasing time of 4-5 days.

Expansion and characterization of adipose tissue-derived stromal cells cultured with low serum medium.

Adipose tissue contains a population of cells that have extensive self-renewal capacity and the ability to differentiate along multiple lineages. In addition, adipose tissue-derived stromal cells (ATSCs) are able to differentiate into various cell types that may be useful for autologous cell transplantation for defects of bone, cartilage, adipose, and tendon, etc. Most protocols for in vitro cultures of ATSCs include fetal bovine serum (FBS) as a nutritional supplement.

Effect of controlled release of fibroblast growth factor-2 from chitosan/fucoidan micro complex-hydrogel on in vitro and in vivo vascularization.

We produced a chitosan/fucoidan micro complex-hydrogel as a carrier for controlled release of heparin binding growth factors such as fibroblast growth factor (FGF)-2. Material consisting of a soluble chitosan (CH-LA) mixed with fucoidan yielded a water-insoluble and injectable hydrogel with filamentous particles. In this study, we examined the ability of the chitosan/fucoidan complex-hydrogel to immobilize FGF-2 and to protect its activity, as well as the controlled release of FGF-2 molecules.

Enhanced healing of mitomycin C-treated wounds in rats using inbred adipose tissue-derived stromal cells within an atelocollagen matrix.

The aim of this study was to evaluate the potential accelerating effects of an adipose tissue-derived stromal cells (ATSC)-containing atelocollagen matrix with silicone membrane (ACMS) for repairing mitomycin C-treated healing-impaired wounds. Mitomycin C was applied to full-thickness skin incisions in this study to create a healing-impaired wound model in rat. After thoroughly washing out the mitomycin C from the wound, ACMS alone or ATSC-containing ACMS was applied to the wounds.

aPKC acts upstream of PAR-1b in both the establishment and maintenance of mammalian epithelial polarity.

Background: aPKC and PAR-1 are required for cell polarity in various contexts. In mammalian epithelial cells, aPKC localizes at tight junctions (TJs) and plays an indispensable role in the development of asymmetric intercellular junctions essential for the establishment and maintenance of apicobasal polarity. On the other hand, one of the mammalian PAR-1 kinases, PAR-1b/EMK1/MARK2, localizes to the lateral membrane in a complimentary manner with aPKC, but little is known about its role in apicobasal polarity of epithelial cells as well as its functional relationship with aPKC.

Self-association of PAR-3-mediated by the conserved N-terminal domain contributes to the development of epithelial tight junctions.

PAR-3 is a scaffold-like PDZ-containing protein that forms a complex with PAR-6 and atypical protein kinase C (PAR-3-atypical protein kinase C-PAR-6 complex) and contributes to the establishment of cell polarity in a wide variety of biological contexts. In mammalian epithelial cells, it localizes to tight junctions, the most apical end of epithelial cell-cell junctions, and contributes to the formation of functional tight junctions. However, the mechanism by which PAR-3 localizes to tight junctions and contributes to their formation remains to be clarified.