Role of actin in epidermal cell indirect adhesion.

În epidermis, Ras can influence proliferation and differentiation; however, regulators of epidermal Ras function are not fully characterized, and Ras effects on growth and differentiation are controversial. EGF induced Ras activation in epidermal cells along with phosphorylation of the multisubstrate docking protein Gab1 and its binding to SHP-2. Expression of mutant Gab1Y627F deficient in SHP-2 binding or dominant-negative SHP-2C459S reduced basal levels of active Ras and downstream MAPK proteins and initiated differentiation. Differentiation triggered by both Gab1Y627F and SHP-2C459S could be blocked by coexpression of active Ras, consistent with Gab1 and SHP-2 action upstream of Ras in this process. To study the role of Gab1 and SHP-2 in tissue, we generated human epidermis overexpressing active Gab1 and SHP-2. Both proteins stimulated proliferation. In contrast, Gab1Y627F and SHP-2C459S inhibited epidermal proliferation and enhanced differentiation. Consistent with a role for Gab1 and SHP-2 in sustaining epidermal Ras/MAPK activity, Gab1−/− murine epidermis displayed lower levels of active Ras and MAPK with postnatal Gab1−/− epidermis, demonstrating the hypoplasia and enhanced differentiation seen previously with transgenic epidermal Ras blockade. These data provide support for a Ras role in promoting epidermal proliferation and opposing differentiation and indicate that Gab1 and SHP-2 promote the undifferentiated epidermal cell state by facilitating Ras/MAPK signaling.

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A novel role of angiotensin II in epidermal cell lineage determination: Angiotensin II promotes the differentiation of mesenchymal stem cells into keratinocytes through the p38 MAPK, JNK and JAK2 signalling pathways

Experimental Dermatology ◽

10.1111/exd.13837 ◽

2019 ◽

Vol 28 (1) ◽

pp. 59-65 ◽

Cited By ~ 4

Author(s):

Xiao Jiang ◽

Fan Wu ◽

Yuan Xu ◽

Jian-Xin Yan ◽

Yin-Di Wu ◽

...

Keyword(s):

Stem Cells ◽

Mesenchymal Stem Cells ◽

Angiotensin Ii ◽

P38 Mapk ◽

Epidermal Cell ◽

Cell Lineage ◽

Signalling Pathways

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Fine structure of sensilla on the ovipositor of the tephritid fly Urophora affinis

Canadian Journal of Zoology ◽

10.1139/z86-147 ◽

1986 ◽

Vol 64 (4) ◽

pp. 973-984 ◽

Cited By ~ 4

Author(s):

R. Y. Zacharuk ◽

R. M. K. W. Lee ◽

D. E. Berube

Keyword(s):

Fine Structure ◽

Epidermal Cell ◽

Fruit Flies ◽

Sheath Cell ◽

Outer Sheath ◽

Dendritic Segment ◽

Tubular Body ◽

Tubular Bodies ◽

Sheath Cells

There are four types of sensilla on the ovipositor blade of Urophora affinis Frauenfeld, one more than was observed on three other species of fruit flies studied by other authors. Three of the types, uniporous gustatory pegs, campaniform organs, and tactile short hairs are common to the four species and generally are in similar positions on the blade. The fourth, uniporous gustatory plates, were noted in U. affinis only. The chemosensilla are innervated by three chemosensory dendrites that terminate below the pore and a mechanosensory dendrite with a tubular body that is attached to a basal cuticular apodeme of the covering cuticle. The dendritic tubular bodies of the campaniform organs and tactile hairs terminate parallel to the surface in a right-angular bend, where they are attached to basal apodemes of the covering cuticle. The chemosensilla and tactile hairs have individual outer and inner sheath cells, but the campaniform organs have individual inner sheath cells only. The part of the ciliary dendritic segment that is encased by the dendritic sheath passes through an epidermal cell, often with several sensilla sharing the same epidermal cell in place of an outer sheath cell. The role of these sensilla during oviposition is discussed.

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Role of xyloglucan breakdown in epidermal cell walls for auxininduced elongation of azuki bean epicotyl segments

Physiologia Plantarum ◽

10.1111/j.1399-3054.1993.tb00136.x ◽

1993 ◽

Vol 87 (2) ◽

pp. 142-147 ◽

Cited By ~ 12

Author(s):

Takayuki Hoson ◽

Yoshiaki Sone ◽

Akira Misaki ◽

Yoshio Masuda

Keyword(s):

Epidermal Cell ◽

Cell Walls ◽

Azuki Bean

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Role of skin surface lipids in UV-induced epidermal cell changes

Archives of Dermatological Research ◽

10.1007/bf00372061 ◽

1991 ◽

Vol 283 (3) ◽

pp. 191-197 ◽

Cited By ~ 41

Author(s):

M. Picardo ◽

C. Zompetta ◽

C. De Luca ◽

M. Cirone ◽

A. Faggioni ◽

...

Keyword(s):

Epidermal Cell ◽

Skin Surface ◽

Surface Lipids ◽

Skin Surface Lipids ◽

Cell Changes

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Supra-physiological levels of Gibberellins/DELLAs alter the patterning, morphology and abundance of root hairs in root tips of A. thaliana seedlings

10.1101/2021.07.15.452505 ◽

2021 ◽

Author(s):

Iva McCarthy-Suarez

Keyword(s):

Gene Expression ◽

Cell Fate ◽

Epidermal Cell ◽

Root Hair ◽

Root Hairs ◽

Root Tip ◽

Spatial Patterning ◽

Root Tips ◽

Root Epidermis

In spite of the known role of gibberellins (GAs), and of their antagonistic proteins, the DELLAs, in leaf hair production, no investigations, however, have assessed their hypothetical function in the production of root hairs. To this aim, the effects of supra-physiological levels of GAs/DELLAs on the spatial patterning of gene expression of the root hair (CPC) and root non-hair (GL2, EGL3 and WER) epidermal cell fate markers, as well as on the distribution, morphology and abundance of root hairs, were studied in root tips of 5-day-old A. thaliana seedlings. Results showed that excessive levels of GAs/DELLAs impaired the spatial patterning of gene expression of the root hair/non-hair epidermal cell fate markers, as well as the arrangement, shape and frequency of root hairs, giving rise to ectopic hairs and ectopic non-hairs, two-haired cells, two-tipped hairs, branched hairs, longer and denser hairs near the root tip under excessive DELLAs, and shorter and scarcer hairs near the root tip under excessive GAs. However, when the gai-1 (GA-insensitive-1) DELLA mutant protein was specifically over-expressed at the root epidermis, no changes in the patterning or abundance of root hairs occurred. Thus, these results suggest that, in seedlings of A. thaliana, the GAs/DELLAs might have a role in regulating the patterning, morphology and abundance of root hairs by acting from the sub-epidermal tissues of the root.

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