scholarly journals Growth control by EGF repeats of the C. elegans Fibulin-1C isoform

2006 ◽  
Vol 175 (2) ◽  
pp. 217-223 ◽  
Author(s):  
Daniel Hesselson ◽  
Judith Kimble
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Growth Control ◽  
Regulatory Function ◽  
C Elegans ◽  
Curr Biol ◽  
Developmental Growth ◽  
Control Growth ◽  
Epidermal Growth ◽  
Type C

Fibulin is a broadly conserved component of the extracellular matrix (ECM). Previous studies have shown that Caenorhabditis elegans FIBULIN-1 (FBL-1) controls the width of the gonad (Hesselson, D., C. Newman, K.W. Kim, and J. Kimble. 2004. Curr. Biol. 14:2005–2010; Kubota, Y., R. Kuroki, and K. Nishiwaki. 2004. Curr. Biol. 14:2011–2018; Muriel, J.M., C. Dong, H. Hutter, and B.E. Vogel. 2005. Development. 132: 4223–4234). In this study, we report that FBL-1 also controls developmental growth and that one isoform of fibulin-1, called FBL-1C, controls both functions by distinct mechanisms. A large FBL-1C fragment, including both epidermal growth factor (EGF) and fibulin-type C domains, is responsible for constraining gonadal width, but a much smaller fragment containing only two complete EGF repeats (EGF1-2C+) is critical for developmental growth. We suggest that the larger fragment serves a scaffolding function to stabilize the basement membrane and that the smaller fragment provides a regulatory function at the cell surface or within the ECM to control growth.

scholarly journals Epithelial Phenotypes in the Developing Human Prostate

2007 ◽  
Vol 55 (9) ◽  
pp. 885-890 ◽  
Author(s):  
Guy Letellier ◽  
Marie-José Perez ◽  
Mokrane Yacoub ◽  
Pierre Levillain ◽  
Olivier Cussenot ◽  
...  
Keyword(s):  
Androgen Receptor ◽  
Growth Factor ◽  
Regulatory Function ◽  
Basal Cells ◽  
Normal Prostate ◽  
Prostate Development ◽  
Proliferation And Apoptosis ◽  
Normal Prostate Tissue ◽  
Epidermal Growth ◽  
Luminal Cells

An intermediate population has been identified among prostate glands called transiently amplifying (TA) cells, which are characterized by coexpression of basal and luminal cytokeratins (CKs), high proliferation, and lack of p27 expression. These cells are rare in the normal adult prostate and increase in pretumoral conditions, but their importance in the developing gland remains unknown. We analyzed fetal prostates for the expression of CKs (5/6, 18, 19) and factors involved in proliferation and apoptosis: p63, Ki67, p27, epidermal growth factor (EGFR), Bcl2, androgen receptor (AR). Immunostaining was performed on a tissue microarray, including 40 prostates from fetuses aged 13-42 weeks and normal prostate tissue from 10 adults. In both solid buds and the basal compartment of canalized glands, cells expressed p63, CK5/6, CK19, CK18, BCL2, EGFR and were p27 negative. Luminal cells of fetal canalized glands continue to express CK19, EGFR, and BCL2, without p27 expression. In contrast, adult epithelial luminal cells showed diffuse AR and p27 expression, without CK19, BCL2, and EGFR staining. Proliferation was high and diffuse in fetal glands and rare and restricted to basal cells in adult glands. These results indicate that most fetal epithelial prostatic cells exhibit the phenotype of TA cells, suggesting their regulatory function in prostate development.

scholarly journals The Ubiquitin-like Protein PLIC-2 Is a Negative Regulator of G Protein-coupled Receptor Endocytosis

2008 ◽  
Vol 19 (3) ◽  
pp. 1252-1260 ◽  
Author(s):  
Elsa-Noah N'Diaye ◽  
Aylin C. Hanyaloglu ◽  
Kimberly K. Kajihara ◽  
Manojkumar A. Puthenveedu ◽  
Ping Wu ◽  
...  
Keyword(s):  
Epidermal Growth Factor Receptor ◽  
Growth Factor ◽  
Epidermal Growth Factor ◽  
G Protein ◽  
Growth Factor Receptor ◽  
Negative Regulator ◽  
Regulatory Function ◽  
Receptor Endocytosis ◽  
Epidermal Growth ◽  
G Protein Coupled

The activity of many signaling receptors is regulated by their endocytosis via clathrin-coated pits (CCPs). For G protein-coupled receptors (GPCRs), recruitment of the adaptor protein arrestin to activated receptors is thought to be sufficient to drive GPCR clustering in CCPs and subsequent endocytosis. We have identified an unprecedented role for the ubiquitin-like protein PLIC-2 as a negative regulator of GPCR endocytosis. Protein Linking IAP to Cytoskeleton (PLIC)-2 overexpression delayed ligand-induced endocytosis of two GPCRs: the V2 vasopressin receptor and β-2 adrenergic receptor, without affecting endocytosis of the transferrin or epidermal growth factor receptor. The closely related isoform PLIC-1 did not affect receptor endocytosis. PLIC-2 specifically inhibited GPCR concentration in CCPs, without affecting membrane recruitment of arrestin-3 to activated receptors or its cellular levels. Depletion of cellular PLIC-2 accelerated GPCR endocytosis, confirming its regulatory function at endogenous levels. The ubiquitin-like domain of PLIC-2, a ligand for ubiquitin-interacting motifs (UIMs), was required for endocytic inhibition. Interestingly, the UIM-containing endocytic adaptors epidermal growth factor receptor protein substrate 15 and Epsin exhibited preferential binding to PLIC-2 over PLIC-1. This differential interaction may underlie PLIC-2 specific effect on GPCR endocytosis. Identification of a negative regulator of GPCR clustering reveals a new function of ubiquitin-like proteins and highlights a cellular requirement for exquisite regulation of receptor dynamics.

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