Neurotractin, A Novel Neurite Outgrowth-promoting Ig-like Protein that Interacts with CEPU-1 and LAMP

Abstract

The formation of axon tracts in nervous system histogenesis is the result of selective axon fasciculation and specific growth cone guidance in embryonic development. One group of proteins implicated in neurite outgrowth, fasciculation, and guidance is the neural members of the Ig superfamily (IgSF). In an attempt to identify and characterize new proteins of this superfamily in the developing nervous system, we used a PCR-based strategy with degenerated primers that represent conserved sequences around the characteristic cysteine residues of Ig-like domains. Using this approach, we identified a novel neural IgSF member, termed neurotractin. This GPI-linked cell surface glycoprotein is composed of three Ig-like domains and belongs to the IgLON subgroup of neural IgSF members. It is expressed in two isoforms with apparent molecular masses of 50 and 37 kD, termed L-form and S-form, respectively. Monoclonal antibodies were used to analyze its biochemical features and histological distribution. Neurotractin is restricted to subsets of developing commissural and longitudinal axon tracts in the chick central nervous system. Recombinant neurotractin promotes neurite outgrowth of telencephalic neurons and interacts with the IgSF members CEPU-1 (K D = 3 × 10−8 M) and LAMP. Our data suggest that neurotractin participates in the regulation of neurite outgrowth in the developing brain.

Diglons are heterodimeric proteins composed of IgLON subunits, and Diglon-CO inhibits neurite outgrowth from cerebellar granule cells

“…These experiments used αLAMP and βCEPU-1, and it remains to be determined whether the inclusion of the β exon modifies either homo-or heterophilic interactions for LAMP or CEPU-1. It is interesting that initial studies of chick Kilon (Neurotractin) described heterophilic interactions between Kilon and CEPU-1, whereas Kilon/ LAMP interactions were considerably weaker and no evidence for homophilic interactions of Kilon was presented (Marg et al, 1999). In addition, recent chemical cross-linking experiments on rat cerebral cortex provide evidence for Kilon-OBCAM heterophilic complexes (Miyata et al, 2003).…”

“…In some cases, little or no response has been observed and, in others, moderate enhancement or inhibition has been seen (Gil et al, 1998;Hancox et al, 1997;Lodge et al, 2001;Mann et al, 1998;Marg et al, 1999;McNamee et al, 2002). Interestingly, the most striking results were obtained with GP55, a glycoprotein isolated from adult brain that contains a mixture of all members of the IgLON family (Clarke and Moss, 1994).…”

The Transcriptional Regulators TAZ and YAP Direct Transforming Growth Factor β-induced Tumorigenic Phenotypes in Breast Cancer Cells

“…The top two genes synergistically induced by TAZ/YAP⅐TEAD and TGF␤ identified in our analysis were NEGR1 and UCA1. NEGR1 encodes a cell adhesion molecule that plays a role in neuronal growth and development (53)(54)(55)(56)(57)(58)(59). UCA1 encodes a long noncoding RNA that is expressed in development, is turned off in homeostatic tissues, and has been found to be highly expressed in bladder carcinomas (60).…”

Application of a new wall-less plate technology to complex multistep cell-based investigations using suspension cells

“…on May 10, 2018. by guest www.bloodjournal.org From proteins have been shown to be involved in cell-to-cell adhesion and to interact homophilically and heterophilically within the family with various binding affinities. [23][24][25][26] Using the optimized washing conditions described previously, we compared the DropArray technology with conventional 384-well plates using a regular automated washing procedure. Here, COS7 (adherent), HEK293T (semiadherent), and HEK293S (suspension-adapted) were transiently transfected with LSAMP, HNT, or OPCML constructs.…”