Identification of a novel contactin-associated transmembrane receptor with multiple domains implicated in protein-protein interactions

Abstract

Barnea et al., 1994;Maurel et al., 1994). It has been expressed on the surface of glial cells binds to the shown that the expression of RPTPβ is restricted to the glycosylphosphatidylinositol (GPI)-anchored recogninervous system. RPTPβ is expressed in cells that have been tion molecule contactin on neuronal cells leading to implicated in neuronal migration and axonal guidance, neurite outgrowth. We describe the cloning of a novel including glial precursors, radial glia and astrocytes (Rauch contactin-associated transmembrane receptor (p190 Canoll et al., 1993). RPTPβ also bears the Caspr) containing a mosaic of domains implicated in HNK-1 carbohydrate epitope that is found in several protein-protein interactions. The extracellular domain neuronal adhesion molecules and was implicated in cell of Caspr contains a neurophilin/coagulation factor recognition and axonal guidance (Rauch et al., 1991). In homology domain, a region related to fibrinogen β/γ, Drosophila, the analogous HRP carbohydrate epitope was epidermal growth factor-like repeats, neurexin motifs found in neural recognition molecules as well as in as well as unique PGY repeats found in a molluscan receptor protein tyrosine phosphatases that are expressed adhesive protein. The cytoplasmic domain of Caspr in the developing nervous system (Desai et al., 1994). It contains a proline-rich sequence capable of binding to was demonstrated recently that loss-of-function mutations a subclass of SH3 domains of signaling molecules.in Drosophila RPTPs result in erroneous pathfinding Caspr and contactin exist as a complex in rat brain of certain motor axons (Desai et al., 1996; Krueger and are bound to each other by means of lateral (cis) et al., 1996). interactions in the plasma membrane. We proposeIn our attempts to identify specific ligands of RPTPβ, that Caspr may function as a signaling component we used soluble, recombinant CAH or FNIII domains of of contactin, enabling recruitment and activation of this receptor phosphatase as specific reagents for the intracellular signaling pathways in neurons. The bindidentification of cellular proteins that bind to RPTPβ. We ing of RPTPβ to the contactin-Caspr complex could have demonstrated that the FNIII repeat binds specifically provide a mechanism for cell-cell communication to glial cells while the CAH domain of RPTPβ binds to between glial cells and neurons during development.neurons or cells of neuronal origin .

Two novel variants in CNTNAP1 in two siblings presenting with congenital hypotonia and hypomyelinating neuropathy

“…CNTNAP1 encodes a contactin-associated transmembrane receptor (Caspr), with high expression level in central and peripheral nervous system. 9 Caspr is localized to the paranodal axoglial junction of myelinated axons. 10 The specific organization of Ranvier nodes and paranodal regions is necessary to action potential saltatory conduction.…”

Arabinogalactan-proteins: structure, expression and function

“…This idea is perhaps most analogous to the animal model in which contactin, a GPI-anchored membrane protein in neurons, interacts with contactin associated protein (Caspr). Caspr is a transmembrane protein that is also found in neuronal membranes and its cytoplasmic domain supposedly triggers a signal transduction cascade [116]. In the case of an fig.…”

Aurora2/BTAK/STK15 is involved in cell cycle checkpoint and cell survival of aggressive non‐Hodgkin's lymphoma

“…Total RNAs from cell lines, normal B cells and primary tumour specimens were size fractionated in 1% agalose/ formaldehyde gels and transferred to nylon membranes as described (Peles et al, 1997). A nylon membrane of multiple human tissue for Northern blot was purchased from OriGene Technologies (Rockville, MD, USA).…”