scholarly journals CRYP-2/cPTPRO is a neurite inhibitory repulsive guidance cue for retinal neurons in vitro

2001 ◽  
Vol 154 (4) ◽  
pp. 867-878 ◽  
Author(s):  
Laurie Stepanek ◽  
Qi Lun Sun ◽  
Jun Wang ◽  
Cong Wang ◽  
John L. Bixby
Keyword(s):  
Growth Cone ◽  
Protein Tyrosine Phosphatases ◽  
Axon Growth ◽  
Extracellular Domain ◽  
Receptor Protein ◽  
Projection Neurons ◽  
Retinal Neurons ◽  
Type Iii ◽  
Guidance Cue

Receptor protein tyrosine phosphatases (RPTPs) are implicated as regulators of axon growth and guidance. Genetic deletions in the fly have shown that type III RPTPs are important in axon pathfinding, but nothing is known about their function on a cellular level. Previous experiments in our lab have identified a type III RPTP, CRYP-2/cPTPRO, specifically expressed during the period of axon outgrowth in the chick brain; cPTPRO is expressed in the axons and growth cones of retinal and tectal projection neurons. We constructed a fusion protein containing the extracellular domain of cPTPRO fused to the Fc portion of mouse immunoglobulin G-1, and used it to perform in vitro functional assays. We found that the extracellular domain of cPTPRO is an antiadhesive, neurite inhibitory molecule for retinal neurons. In addition, cPTPRO had potent growth cone collapsing activity in vitro, and locally applied gradients of cPTPRO repelled growing retinal axons. This chemorepulsive effect could be regulated by the level of cGMP in the growth cone. Immunohistochemical examination of the retina indicated that cPTPRO has at least one heterophilic binding partner in the retina. Taken together, our results indicate that cPTPRO may act as a guidance cue for retinal ganglion cells during vertebrate development.

scholarly journals Nestin in immature embryonic neurons affects axon growth cone morphology and Semaphorin3a sensitivity

2019 ◽  
Vol 30 (10) ◽  
pp. 1214-1229 ◽  
Author(s):  
C. J. Bott ◽  
C. G. Johnson ◽  
C. C. Yap ◽  
N. D. Dwyer ◽  
K. A. Litwa ◽  
...  
Keyword(s):  
Growth Cone ◽  
Intermediate Filament ◽  
Cortical Neurons ◽  
Axon Growth ◽  
Neural Progenitors ◽  
Spatial Modulation ◽  
Nestin Expression ◽  
Guidance Cue ◽  
Newborn Neurons

Correct wiring in the neocortex requires that responses to an individual guidance cue vary among neurons in the same location, and within the same neuron over time. Nestin is an atypical intermediate filament expressed strongly in neural progenitors and is thus used widely as a progenitor marker. Here we show a subpopulation of embryonic cortical neurons that transiently express nestin in their axons. Nestin expression is thus not restricted to neural progenitors, but persists for 2–3 d at lower levels in newborn neurons. We found that nestin-expressing neurons have smaller growth cones, suggesting that nestin affects cytoskeletal dynamics. Nestin, unlike other intermediate filament subtypes, regulates cdk5 kinase by binding the cdk5 activator p35. Cdk5 activity is induced by the repulsive guidance cue Semaphorin3a (Sema3a), leading to axonal growth cone collapse in vitro. Therefore, we tested whether nestin-expressing neurons showed altered responses to Sema3a. We find that nestin-expressing newborn neurons are more sensitive to Sema3a in a roscovitine-sensitive manner, whereas nestin knockdown results in lowered sensitivity to Sema3a. We propose that nestin functions in immature neurons to modulate cdk5 downstream of the Sema3a response. Thus, the transient expression of nestin could allow temporal and/or spatial modulation of a neuron’s response to Sema3a, particularly during early axon guidance.

scholarly journals Nestin in immature embryonic neurons regulates axon growth cone morphology and Semaphorin3a sensitivity

2017 ◽  
Author(s):  
C.J. Bott ◽  
C. G. Johnson ◽  
C.C. Yap ◽  
N.D. Dwyer ◽  
K.A. Litwa ◽  
...  
Keyword(s):  
Growth Cone ◽  
Intermediate Filament ◽  
Cortical Neurons ◽  
Axon Growth ◽  
Neural Progenitors ◽  
Nestin Expression ◽  
Guidance Cue ◽  
Cytoskeletal Dynamics ◽  
Newborn Neurons

AbstractCorrect wiring in the neocortex requires that responses to an individual guidance cue vary among neurons in the same location, and within the same neuron over time. Nestin is an atypical intermediate filament expressed highly in neural progenitors and is thus used widely as a progenitor marker. Here we show a subpopulation of embryonic cortical neurons which transiently express nestin in their axons. Nestin expression is thus not restricted to neural progenitors but persists at lower levels in some newborn neurons for 2-3 days. We found that nestin-expressing neurons have smaller growth cones, suggesting that nestin affects cytoskeletal dynamics. Nestin, unlike other intermediate filament subtypes, regulates cdk5 kinase. Cdk5 activity is induced by the repulsive guidance cue Sema3a leading to growth cone collapse in vitro. Therefore, we tested whether nestin-expressing neurons showed altered responses to Sema3a. We find that nestin-expressing newborn neurons are more sensitive to Sema3a in a roscovitine-sensitive manner, whereas nestin knockdown results in lowered sensitivity to Sema3a. We propose that nestin functions in immature neurons to modulate cdk5 and thereby the Sema3a response. Thus, the transient expression of nestin could allow for temporal modulation of a neuron's response to Sema3a particularly during early axon guidance decisions.

Inhibition of motor axon growth by T-cadherin substrata

Development ◽  
1996 ◽  
Vol 122 (10) ◽  
pp. 3163-3171 ◽  
Author(s):  
B.J. Fredette ◽  
J. Miller ◽  
B. Ranscht
Keyword(s):  
Motor Neurons ◽  
Axon Growth ◽  
Neurite Growth ◽  
Motor Axon ◽  
Spinal Motor Neurons ◽  
Guidance Cue ◽  
Spinal Motor ◽  
Neuron Populations ◽  
Muscle Innervation

As spinal motor neurons project to their hindlimb targets, their growth cones avoid particular regions along their pathway. T-cadherin is discretely distributed in the avoided caudal sclerotome and on extrasynaptic muscle surfaces (B. J. Fredette and B. Ranscht (1994) J. Neurosci. 14, 7331–7346), and therefore, the ability of T-cadherin to inhibit neurite growth was tested in vitro. T-cadherin inhibited neurite extension from select neuron populations both as a substratum, and as a soluble recombinant protein. Anti-T-cadherin antibodies neutralized the inhibition. Spinal motor neurons were inhibited only during the stages of axon growth across the sclerotome and muscle innervation. Inhibitory responses corresponded to neuronal T-cadherin expression, suggesting a homophilic binding mechanism. These results suggest that T-cadherin is a negative guidance cue for motor axon projections.

scholarly journals Structural basis of liprin-α-promoted LAR-RPTP clustering for modulation of phosphatase activity

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Xingqiao Xie ◽  
Ling Luo ◽  
Mingfu Liang ◽  
Wenchao Zhang ◽  
Ting Zhang ◽  
...  
Keyword(s):  
Phosphatase Activity ◽  
Neuronal Development ◽  
Protein Tyrosine Phosphatases ◽  
Axon Growth ◽  
Binding Mode ◽  
Receptor Protein ◽  
Structural Basis ◽  
Cellular Analysis ◽  
Catalytically Active ◽  
Receptor Protein Tyrosine Phosphatases

AbstractLeukocyte common antigen-related receptor protein tyrosine phosphatases (LAR-RPTPs) are cell adhesion molecules involved in mediating neuronal development. The binding of LAR-RPTPs to extracellular ligands induces local clustering of LAR-RPTPs to regulate axon growth and synaptogenesis. LAR-RPTPs interact with synaptic liprin-α proteins via the two cytoplasmic phosphatase domains, D1 and D2. Here we solve the crystal structure of LAR_D1D2 in complex with the SAM repeats of liprin-α3, uncovering a conserved two-site binding mode. Cellular analysis shows that liprin-αs robustly promote clustering of LAR in cells by both the liprin-α/LAR interaction and the oligomerization of liprin-α. Structural analysis reveals a unique homophilic interaction of LAR via the catalytically active D1 domains. Disruption of the D1/D1 interaction diminishes the liprin-α-promoted LAR clustering and increases tyrosine dephosphorylation, demonstrating that the phosphatase activity of LAR is negatively regulated by forming clusters. Additionally, we find that the binding of LAR to liprin-α allosterically regulates the liprin-α/liprin-β interaction.

scholarly journals No Obvious Abnormality in Mice Deficient in Receptor Protein Tyrosine Phosphatase β

2000 ◽  
Vol 20 (20) ◽  
pp. 7706-7715 ◽  
Author(s):  
S. Harroch ◽  
M. Palmeri ◽  
J. Rosenbluth ◽  
A. Custer ◽  
M. Okigaki ◽  
...  
Keyword(s):  
Nervous System ◽  
Neurite Outgrowth ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Structural Features ◽  
Receptor Protein ◽  
Protein Tyrosine ◽  
Deficient Mice

ABSTRACT The development of neurons and glia is governed by a multitude of extracellular signals that control protein tyrosine phosphorylation, a process regulated by the action of protein tyrosine kinases and protein tyrosine phosphatases (PTPs). Receptor PTPβ (RPTPβ; also known as PTPζ) is expressed predominantly in the nervous system and exhibits structural features common to cell adhesion proteins, suggesting that this phosphatase participates in cell-cell communication. It has been proposed that the three isoforms of RPTPβ play a role in regulation of neuronal migration, neurite outgrowth, and gliogenesis. To investigate the biological functions of this PTP, we have generated mice deficient in RPTPβ. RPTPβ-deficient mice are viable, are fertile, and showed no gross anatomical alterations in the nervous system or other organs. In contrast to results of in vitro experiments, our study demonstrates that RPTPβ is not essential for neurite outgrowth and node formation in mice. The ultrastructure of nerves of the central nervous system in RPTPβ-deficient mice suggests a fragility of myelin. However, conduction velocity was not altered in RPTPβ-deficient mice. The normal development of neurons and glia in RPTPβ-deficient mice demonstrates that RPTPβ function is not necessary for these processes in vivo or that loss of RPTPβ can be compensated for by other PTPs expressed in the nervous system.

Control of retinal ganglion cell axon growth: a new role for Sonic hedgehog

Development ◽  
2001 ◽  
Vol 128 (20) ◽  
pp. 3927-3936 ◽  
Author(s):  
Françoise Trousse ◽  
Elisa Martí ◽  
Peter Gruss ◽  
Miguel Torres ◽  
Paola Bovolenta
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cell ◽  
Sonic Hedgehog ◽  
Growth Cone ◽  
Ectopic Expression ◽  
Axon Growth ◽  
Negative Regulator ◽  
Retinal Ganglion ◽  
Ventral Midline

Retinal ganglion cell (RGC) axons grow towards the diencephalic ventral midline during embryogenesis guided by cues whose nature is largely unknown. We provide in vitro and in vivo evidence for a novel role of Sonic hedgehog (SHH) as a negative regulator of growth cone movement. SHH suppresses both the number and the length of neurites emerging from the chick retina but not from neural tube or dorsal root ganglia explants, without interfering with their rate of proliferation and differentiation. Similarly, retroviral-mediated ectopic expression of Shh along the chick visual pathway greatly interferes the growth of RGC axons. Upon SHH addition to grown neurites, the intracellular level of cAMP decreases, suggesting that the dampening of growth cone extension mediated by SHH may involve interaction with its receptor Patched which is expressed by RGC. Based on these findings, we propose that Shh expression at the chiasm border defines a constrained pathway within the ventral midline which serves to guide the progression of RGC axons.

scholarly journals Transmembrane glycoprotein gp150 is a substrate for receptor tyrosine phosphatase DPTP10D in Drosophila cells.

1997 ◽  
Vol 17 (12) ◽  
pp. 6859-6867 ◽  
Author(s):  
S J Fashena ◽  
K Zinn
Keyword(s):  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Cytoplasmic Domain ◽  
Receptor Protein ◽  
S2 Cells ◽  
Wild Type ◽  
Downstream Signaling ◽  
Transmembrane Glycoprotein

We have begun to explore the downstream signaling pathways of receptor protein tyrosine phosphatases (RPTPs) that control axon guidance decisions in the Drosophila central nervous system. We have focused our studies on the adhesion molecule-like gp150 protein, which binds directly to and is an in vitro substrate for the RPTP DPTP10D. Here we show that gp150 and DPTP10D form stable complexes in Drosophila Schneider 2 (S2) cells and in wild-type larval tissue. We also demonstrate that the DPTP10D cytoplasmic domain is sufficient to confer binding to gp150. gp150 has a short cytoplasmic domain containing four tyrosines, all found within sequences similar to immunoreceptor family tyrosine-based activation motifs (ITAMs). We demonstrate that gp150 is tyrosine phosphorylated in wild-type larvae. In S2 cells, gp150 becomes tyrosine phosphorylated following incubation with PTP inhibitors or upon coexpression of the Dsrc tyrosine kinase. Phosphorylated Dsrc and an unknown 40-kDa phosphoprotein form stable complexes with gp150, thereby implicating them in a putative gp150 signaling pathway. When coexpressed with gp150, either full-length DPTP10D or its cytoplasmic domain mediates gp150 dephosphorylation whereas a catalytically inactive DPTP10D cytoplasmic domain does not. The neural RPTP DPTP99A can also induce gp150 dephosphorylation but does not coimmunoprecipitate with gp150. Taken together, the results suggest that gp150 transduces signals via phosphorylation of its ITAM-like elements. Phosphotyrosines on gp150 might function as binding sites for downstream signaling molecules, thereby initiating a signaling cascade that could be modulated in vivo by RPTPs such as DPTP10D.

scholarly journals CD45 and RPTPα display different protein tyrosine phosphatase activities in T lymphocytes

1997 ◽  
Vol 327 (3) ◽  
pp. 867-876 ◽  
Author(s):  
H. W. David NG ◽  
D. Mojgan JABALI ◽  
Arpita MAITI ◽  
Peter BORODCHAK ◽  
W. Kenneth HARDER ◽  
...  
Keyword(s):  
T Cells ◽  
Tyrosine Phosphatase ◽  
Protein Tyrosine Phosphatases ◽  
Cell Receptor ◽  
Artificial Substrates ◽  
Receptor Protein ◽  
Tyrosine Phosphatases ◽  
Recombinant Enzymes ◽  
Protein Tyrosine

To examine the substrate specificity and function of two receptor protein tyrosine phosphatases, CD45 and RPTPα, RPTPα was expressed in a CD45-, T-cell receptor (TCR)+, BW5147 T-lymphoma cell. High levels of expression of RPTPα did not fully restore either proximal or distal TCR-mediated signalling events. RPTPα was unable to reconstitute the phosphorylation of CD3ζ and did not increase the expression of the activation marker, CD69, on stimulation with TCR/CD3. RPTPα did not significantly alter the phosphorylation state or kinase activity of two CD45 substrates, p56lck or p59fyn, suggesting that RPTPα does not have the same specificity or function as CD45 in T-cells. Further comparison of the two phosphatases indicated that immunoprecipitated RPTPα was approx. one-seventh to one-tenth as active as CD45 when tested against artificial substrates. This difference in activity was also observed in vitro with purified recombinant enzymes at physiological pH. Additional analysis with Src family phosphopeptides and recombinant p56lck as substrates indicated that CD45 was consistently more active than RPTPα, having both higher Vmax and lower Km values. Thus CD45 is intrinsically a much more active phosphatase than RPTPα, which provides one reason why RPTPα cannot effectively dephosphorylate p56lck and substitute for CD45 in T-cells. This work establishes that these two related protein tyrosine phosphatases are not interchangeable in T-cells and that this is due, at least in part, to quantitative differences in phosphatase activity.

scholarly journals Selective rab11 transport and the intrinsic regenerative ability of CNS axons

eLife ◽  
2017 ◽  
Vol 6 ◽  
Author(s):  
Hiroaki Koseki ◽  
Matteo Donegá ◽  
Brian YH Lam ◽  
Veselina Petrova ◽  
Susan van Erp ◽  
...  
Keyword(s):  
Growth Cone ◽  
Axon Growth ◽  
Retrograde Transport ◽  
Progressive Decline ◽  
Regenerative Ability

Neurons lose intrinsic axon regenerative ability with maturation, but the mechanism remains unclear. Using an in-vitro laser axotomy model, we show a progressive decline in the ability of cut CNS axons to form a new growth cone and then elongate. Failure of regeneration was associated with increased retraction after axotomy. Transportation into axons becomes selective with maturation; we hypothesized that selective exclusion of molecules needed for growth may contribute to regeneration decline. With neuronal maturity rab11 vesicles (which carry many molecules involved in axon growth) became selectively targeted to the somatodendritic compartment and excluded from axons by predominant retrograde transport However, on overexpression rab11 was mistrafficked into proximal axons, and these axons showed less retraction and enhanced regeneration after axotomy. These results suggest that the decline of intrinsic axon regenerative ability is associated with selective exclusion of key molecules, and that manipulation of transport can enhance regeneration.

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