The L6 domain tetraspanin Tm4sf4 regulates endocrine pancreas differentiation and directed cell migration
- Authors
- Anderson, K.R., Singer, R.A., Balderes, D.A., Hernandez-Lagunas, L., Johnson, C.W., Artinger, K.B., and Sussel, L.
- ID
- ZDB-PUB-110719-2
- Date
- 2011
- Source
- Development (Cambridge, England) 138(15): 3213-3224 (Journal)
- Registered Authors
- Anderson, Keith, Artinger, Kristin Bruk, Johnson, Christopher
- Keywords
- Nkx2.2, Tm4sf4, pancreas, islet cell, differentiation, mouse, zebrafish
- MeSH Terms
-
- Mice, Knockout
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism*
- Animals
- Mice
- Humans
- Cell Differentiation/physiology*
- Stem Cells/cytology
- Stem Cells/physiology
- Membrane Proteins/genetics
- Membrane Proteins/metabolism*
- Amino Acid Sequence
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Molecular Sequence Data
- Cell Line
- Zebrafish/anatomy & histology
- Zebrafish/embryology
- Zebrafish/growth & development
- Zebrafish/metabolism
- Basic Helix-Loop-Helix Transcription Factors/genetics
- Basic Helix-Loop-Helix Transcription Factors/metabolism
- Ghrelin/genetics
- Ghrelin/metabolism
- Cell Movement/physiology*
- Sequence Alignment
- Zebrafish Proteins/genetics
- Zebrafish Proteins/metabolism*
- Membrane Glycoproteins/genetics
- Membrane Glycoproteins/metabolism*
- Gene Expression Regulation, Developmental*
- Islets of Langerhans/cytology
- Islets of Langerhans/embryology*
- Islets of Langerhans/growth & development*
- Islets of Langerhans/metabolism
- Transcription Factors/genetics
- Transcription Factors/metabolism*
- rho GTP-Binding Proteins/genetics
- rho GTP-Binding Proteins/metabolism
- PubMed
- 21750032 Full text @ Development
The homeodomain transcription factor Nkx2.2 is essential for pancreatic development and islet cell type differentiation. We have identified Tm4sf4, an L6 domain tetraspanin family member, as a transcriptional target of Nkx2.2 that is greatly upregulated during pancreas development in Nkx2.2-/- mice. Tetraspanins and L6 domain proteins recruit other membrane receptors to form active signaling centers that coordinate processes such as cell adhesion, migration and differentiation. In this study, we determined that Tm4sf4 is localized to the ductal epithelial compartment and is prominent in the Ngn3+ islet progenitor cells. We also established that pancreatic tm4sf4 expression and regulation by Nkx2.2 is conserved during zebrafish development. Loss-of-function studies in zebrafish revealed that tm4sf4 inhibits α and β cell specification, but is necessary for ε cell fates. Thus, Tm4sf4 functional output opposes that of Nkx2.2. Further investigation of how Tm4sf4 functions at the cellular level in vitro showed that Tm4sf4 inhibits Rho-activated cell migration and actin organization in a ROCK-independent fashion. We propose that the primary role of Nkx2.2 is to inhibit Tm4sf4 in endocrine progenitor cells, allowing for delamination, migration and/or appropriate cell fate decisions. Identification of a role for Tm4sf4 during endocrine differentiation provides insight into islet progenitor cell behaviors and potential targetable regenerative mechanisms.