scholarly journals HTT is a repressor of ABL activity required for APP induced axonal growth

2019 ◽  
Author(s):  
Claire Marquilly ◽  
Germain Busto ◽  
Brittany S. Leger ◽  
Edward Giniger ◽  
James A. Walker ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Axon Growth ◽  
Axonal Growth ◽  
Negative Regulator ◽  
Mushroom Bodies ◽  
Abl Tyrosine Kinase ◽  
Downstream Effector ◽  
Similar Phenotype ◽  
Clear Increase

ABSTRACTABL tyrosine kinase activity controls several aspects of development including axon patterning. Amyloid precursor protein (APP) is linked to Alzheimer’s disease and previous work established that ABL is a downstream effector in an Appl, the Drosophila App ortholog, signaling pathway which modulates axon outgrowth in the mushroom bodies (MBs), the fly memory center. Here we show that Abl is required for the MB neuron axonal growth. Importantly, both Abl overexpression and lack of expression produce a similar phenotype in the MBs indicating the necessity of tightly regulating ABL activity. We find that the fly huntingtin protein (HTT), the homolog of the protein involved in Huntington’s disease, behaves genetically as a repressor of ABL activity. Supporting this, FRET-based measurements of in vivo ABL activity in the MBs reveal a clear increase in its activity when HTT levels are reduced. Thus, in addition to its many other reported roles, HTT acts as a negative regulator of ABL activity, at least in the MBs, to maintain its appropriate physiological levels necessary for axon growth.

scholarly journals Htt is a repressor of Abl activity required for APP-induced axonal growth

PLoS Genetics ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. e1009287
Author(s):  
Claire Marquilly ◽  
Germain U. Busto ◽  
Brittany S. Leger ◽  
Ana Boulanger ◽  
Edward Giniger ◽  
...  
Keyword(s):  
Kinase Activity ◽  
Developmental Stages ◽  
Neurodegenerative Disorder ◽  
Axon Growth ◽  
Axon Outgrowth ◽  
Developmental Defects ◽  
Abl Kinase ◽  
Abl Tyrosine Kinase ◽  
Polyglutamine Tract

Huntington’s disease is a progressive autosomal dominant neurodegenerative disorder caused by the expansion of a polyglutamine tract at the N-terminus of a large cytoplasmic protein. The Drosophila huntingtin (htt) gene is widely expressed during all developmental stages from embryos to adults. However, Drosophila htt mutant individuals are viable with no obvious developmental defects. We asked if such defects could be detected in htt mutants in a background that had been genetically sensitized to reveal cryptic developmental functions. Amyloid precursor protein (APP) is linked to Alzheimer’s disease. Appl is the Drosophila APP ortholog and Appl signaling modulates axon outgrowth in the mushroom bodies (MBs), the learning and memory center in the fly, in part by recruiting Abl tyrosine kinase. Here, we find that htt mutations suppress axon outgrowth defects of αβ neurons in Appl mutant MB by derepressing the activity of Abl. We show that Abl is required in MB αβ neurons for their axon outgrowth. Importantly, both Abl overexpression and lack of expression produce similar phenotypes in the MBs, indicating the necessity of tightly regulating Abl activity. We find that Htt behaves genetically as a repressor of Abl activity, and consistent with this, in vivo FRET-based measurements reveal a significant increase in Abl kinase activity in the MBs when Htt levels are reduced. Thus, Appl and Htt have essential but opposing roles in MB development, promoting and suppressing Abl kinase activity, respectively, to maintain the appropriate intermediate level necessary for axon growth.

scholarly journals Frizzled3 controls axonal development in distinct populations of cranial and spinal motor neurons

eLife ◽  
2013 ◽  
Vol 2 ◽  
Author(s):  
Zhong L Hua ◽  
Philip M Smallwood ◽  
Jeremy Nathans
Keyword(s):  
Cell Death ◽  
Motor Neurons ◽  
Planar Cell Polarity ◽  
Motor Nerve ◽  
Normal Wave ◽  
Axon Growth ◽  
Axonal Growth ◽  
Cell Complexes ◽  
Developing Neurons

Disruption of the Frizzled3 (Fz3) gene leads to defects in axonal growth in the VIIth and XIIth cranial motor nerves, the phrenic nerve, and the dorsal motor nerve in fore- and hindlimbs. In Fz3−/− limbs, dorsal axons stall at a precise location in the nerve plexus, and, in contrast to the phenotypes of several other axon path-finding mutants, Fz3−/− dorsal axons do not reroute to other trajectories. Affected motor neurons undergo cell death 2 days prior to the normal wave of developmental cell death that coincides with innervation of muscle targets, providing in vivo evidence for the idea that developing neurons with long-range axons are programmed to die unless their axons arrive at intermediate targets on schedule. These experiments implicate planar cell polarity (PCP) signaling in motor axon growth and they highlight the question of how PCP proteins, which form cell–cell complexes in epithelia, function in the dynamic context of axonal growth.

scholarly journals Activation of tyrosinase kinase and microfilament-binding functions of c-abl by bcr sequences in bcr/abl fusion proteins.

1991 ◽  
Vol 11 (3) ◽  
pp. 1553-1565 ◽  
Author(s):  
J R McWhirter ◽  
J Y Wang
Keyword(s):  
Amino Acids ◽  
Tyrosine Kinase ◽  
Fusion Proteins ◽  
Kinase Activity ◽  
Lymphoblastic Leukemia ◽  
Myelogenous Leukemia ◽  
Tyrosine Kinase Activity ◽  
Abl Tyrosine Kinase ◽  
Binding Function

Chronic myelogenous leukemia and one type of acute lymphoblastic leukemia are characterized by a 9;22 chronosome translocation in which 5' sequences of the bcr gene become fused to the c-abl proto-oncogene. The resulting chimeric genes encode bcr/abl fusion proteins which have deregulated tyrosine kinase activity and appear to play an important role in induction of these leukemias. A series of bcr/abl genes were constructed in which nested deletions of the bcr gene were fused to the c-abl gene. The fusion proteins encoded by these genes were assayed for autophosphorylation in vivo and for differences in subcellular localization. Our results demonstrate that bcr sequences activate two functions of c-abl; the tyrosine kinase activity and a previously undescribed microfilament-binding function. Two regions of bcr which activate these functions to different degrees have been mapped: amino acids 1 to 63 were strongly activating and amino acids 64 to 509 were weakly activating. The tyrosine kinase and microfilament-binding functions were not interdependent, as a kinase defective bcr/abl mutant still associated with actin filaments and a bcr/abl mutant lacking actin association still had deregulated kinase activity. Modification of actin filament functions by the bcr/abl tyrosine kinase may be an important event in leukemogenesis.

scholarly journals Interaction of activated Cdc42-associated tyrosine kinase ACK2 with HSP90

2004 ◽  
Vol 382 (1) ◽  
pp. 199-204 ◽  
Author(s):  
Wannian YANG ◽  
Jaclyn M. JANSEN ◽  
Qiong LIN ◽  
Sabrina CANOVA ◽  
Richard A. CERIONE ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Heat Shock Protein 90 ◽  
Kinase Domain ◽  
Atpase Inhibitor ◽  
Sorting Nexin ◽  
Downstream Effector ◽  
Tyrosine Kinase 2 ◽  
Functional Complex

ACK2 (activated Cdc42-associated tyrosine kinase 2) is a specific downstream effector for Cdc42, a member of the Rho family of small G-proteins. ACK2 interacts with clathrin, an endocytic vesicle coating protein, and SH3PX1, a sorting nexin, and is involved in clathrin-mediated endocytosis. While searching for proteins that interact with ACK2, we found that HSP90 (heat-shock protein 90) binds to ACK2. Analysis of a series of truncation mutants of ACK2 has defined the regions within the kinase domain of ACK2 that are required for binding to HSP90. The binding of HSP90 to ACK2 is blocked upon treatment with geldanamycin, an HSP90-specific ATPase inhibitor, and is required for the in vivo kinase activity of ACK2 and its association with Cdc42. Overall, our data suggest a novel mechanism of regulation in which HSP90 serves as a regulatory component in an ACK2 functional complex and plays a role in sustaining its kinase activity.

Detection of c-abl tyrosine kinase activity in vitro permits direct comparison of normal and altered abl gene products

1985 ◽  
Vol 5 (11) ◽  
pp. 3116-3123
Author(s):  
J B Konopka ◽  
O N Witte
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Myelogenous Leukemia ◽  
Gene Products ◽  
Tyrosine Kinase Activity ◽  
Abl Kinase ◽  
Abl Tyrosine Kinase ◽  
Assay Conditions

The v-abl transforming protein P160v-abl and the P210c-abl gene product of the translocated c-abl gene in Philadelphia chromosome-positive chronic myelogenous leukemia cells have tyrosine-specific protein kinase activity. Under similar assay conditions the normal c-abl gene products, murine P150c-abl and human P145c-abl, lacked detectable kinase activity. Reaction conditions were modified to identify conditions which would permit the detection of c-abl tyrosine kinase activity. It was found that the Formalin-fixed Staphylococcus aureus formerly used for immunoprecipitation inhibits in vitro abl kinase activity. In addition, the sodium dodecyl sulfate and deoxycholate detergents formerly used in the cell lysis buffer were found to decrease recovered abl kinase activity. The discovery of assay conditions for c-abl kinase activity now makes it possible to compare P150c-abl and P145c-abl kinase activity with the altered abl proteins P160v-abl and P210c-abl. Although all of the abl proteins have in vitro tyrosine kinase activity, they differ in the way they utilize themselves as substrates in vitro. Comparison of in vitro and in vivo tyrosine phosphorylation sites of the abl proteins suggests that they function differently in vivo. The development of c-abl kinase assay conditions should be useful in elucidating c-abl function.

scholarly journals Detection of c-abl tyrosine kinase activity in vitro permits direct comparison of normal and altered abl gene products.

1985 ◽  
Vol 5 (11) ◽  
pp. 3116-3123 ◽  
Author(s):  
J B Konopka ◽  
O N Witte
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Myelogenous Leukemia ◽  
Gene Products ◽  
Tyrosine Kinase Activity ◽  
Abl Kinase ◽  
Abl Tyrosine Kinase ◽  
Assay Conditions

The v-abl transforming protein P160v-abl and the P210c-abl gene product of the translocated c-abl gene in Philadelphia chromosome-positive chronic myelogenous leukemia cells have tyrosine-specific protein kinase activity. Under similar assay conditions the normal c-abl gene products, murine P150c-abl and human P145c-abl, lacked detectable kinase activity. Reaction conditions were modified to identify conditions which would permit the detection of c-abl tyrosine kinase activity. It was found that the Formalin-fixed Staphylococcus aureus formerly used for immunoprecipitation inhibits in vitro abl kinase activity. In addition, the sodium dodecyl sulfate and deoxycholate detergents formerly used in the cell lysis buffer were found to decrease recovered abl kinase activity. The discovery of assay conditions for c-abl kinase activity now makes it possible to compare P150c-abl and P145c-abl kinase activity with the altered abl proteins P160v-abl and P210c-abl. Although all of the abl proteins have in vitro tyrosine kinase activity, they differ in the way they utilize themselves as substrates in vitro. Comparison of in vitro and in vivo tyrosine phosphorylation sites of the abl proteins suggests that they function differently in vivo. The development of c-abl kinase assay conditions should be useful in elucidating c-abl function.

scholarly journals The retinoblastoma protein physically associates with the human cdc2 kinase.

1992 ◽  
Vol 12 (3) ◽  
pp. 971-980 ◽  
Author(s):  
Q J Hu ◽  
J A Lees ◽  
K J Buchkovich ◽  
E Harlow
Keyword(s):  
Cell Cycle ◽  
Kinase Activity ◽  
Susceptibility Gene ◽  
Biochemical Properties ◽  
Protein Product ◽  
S Phase ◽  
Negative Regulator ◽  
Cdc2 Kinase ◽  
Related Enzyme

The protein product (pRB) of the retinoblastoma susceptibility gene functions as a negative regulator of cell proliferation, and its activity appears to be modulated by phosphorylation. Using a new panel of anti-human pRB monoclonal antibodies, we have investigated the biochemical properties of this protein. These antibodies have allowed us to detect a pRB-associated kinase that has been identified as the cell cycle-regulating kinase p34cdc2 or a closely related enzyme. Since this associated kinase phosphorylates pRB at most of the sites used in vivo, these results suggest that this kinase is one of the major regulators of pRB. The associated kinase activity follows the pattern of phosphorylation seen for pRB in vivo. The associated kinase activity is not seen in the G1 phase but appears in the S phase, and the levels continue to increase throughout the remainder of the cell cycle.

Activation of tyrosinase kinase and microfilament-binding functions of c-abl by bcr sequences in bcr/abl fusion proteins

1991 ◽  
Vol 11 (3) ◽  
pp. 1553-1565
Author(s):  
J R McWhirter ◽  
J Y Wang
Keyword(s):  
Amino Acids ◽  
Tyrosine Kinase ◽  
Fusion Proteins ◽  
Kinase Activity ◽  
Lymphoblastic Leukemia ◽  
Myelogenous Leukemia ◽  
Tyrosine Kinase Activity ◽  
Abl Tyrosine Kinase ◽  
Binding Function

Chronic myelogenous leukemia and one type of acute lymphoblastic leukemia are characterized by a 9;22 chronosome translocation in which 5' sequences of the bcr gene become fused to the c-abl proto-oncogene. The resulting chimeric genes encode bcr/abl fusion proteins which have deregulated tyrosine kinase activity and appear to play an important role in induction of these leukemias. A series of bcr/abl genes were constructed in which nested deletions of the bcr gene were fused to the c-abl gene. The fusion proteins encoded by these genes were assayed for autophosphorylation in vivo and for differences in subcellular localization. Our results demonstrate that bcr sequences activate two functions of c-abl; the tyrosine kinase activity and a previously undescribed microfilament-binding function. Two regions of bcr which activate these functions to different degrees have been mapped: amino acids 1 to 63 were strongly activating and amino acids 64 to 509 were weakly activating. The tyrosine kinase and microfilament-binding functions were not interdependent, as a kinase defective bcr/abl mutant still associated with actin filaments and a bcr/abl mutant lacking actin association still had deregulated kinase activity. Modification of actin filament functions by the bcr/abl tyrosine kinase may be an important event in leukemogenesis.

scholarly journals Fidgetin-like 2 is a novel negative regulator of axonal growth and can be targeted to promote functional nerve regeneration after injury

2020 ◽  
Author(s):  
Lisa Baker ◽  
Moses Tar ◽  
Guillermo Villegas ◽  
Rabab Charafeddine ◽  
Adam Kramer ◽  
...  
Keyword(s):  
Peripheral Nerve ◽  
Nerve Regeneration ◽  
Nerve Injury ◽  
Peripheral Nerve Injury ◽  
Critical Role ◽  
Axon Growth ◽  
Axonal Growth ◽  
Negative Regulator ◽  
Neural Regeneration

AbstractThe microtubule (MT) cytoskeleton plays a critical role in axon growth and guidance. Here, we identify the MT severing enzyme fidgetin-like 2 (FL2) as a negative regulator of axonal regeneration and a potential therapeutic target for promoting neural regeneration after injury. Genetic knockout of FL2 in cultured adult dorsal root ganglion (DRG) neurons resulted in longer axons and attenuated growth cone retraction in response to inhibitory molecules. Given the axonal growth-promoting effects of FL2 depletion in vitro, we tested whether the enzyme could be targeted to promote regeneration in a rodent model of peripheral nerve injury. In the model used in our experiments, the cavernous nerves (CN) are either crushed or transected, mimicking nerve injury caused by radical prostatectomy (RP). As with patients, CN injury results in erectile dysfunction, for which there are presently poor treatment options. At the time of injury, FL2-siRNA or control-siRNA was applied to the site using nanoparticles or chondroitin sulfate microgels as delivery agents. Treatment significantly enhanced functional nerve recovery, as determined by cavernosometry (measurements of corporal blood pressure in response to electrostimulation of the nerve). Remarkably, following complete bilateral nerve transection, visible and functional nerve regeneration was observed in 7 out of 8 animals treated with FL2-siRNA. In contrast, no control-siRNA treated animals showed regeneration. These observations suggest a novel therapeutic approach to treat peripheral nerve injury, particularly injuries resulting from surgical procedures such as RP, where treatments depleting FL2 could be applied locally at the time of injury.

scholarly journals Constitutive Association of BRCA1 and c-Abl and Its ATM-Dependent Disruption after Irradiation

2002 ◽  
Vol 22 (12) ◽  
pp. 4020-4032 ◽  
Author(s):  
Nicolas Foray ◽  
Didier Marot ◽  
Voahangy Randrianarison ◽  
Nicole Dalla Venezia ◽  
Didier Picard ◽  
...  
Keyword(s):  
Tyrosine Kinase ◽  
Kinase Activity ◽  
Direct Interaction ◽  
Cell Cycle Checkpoint ◽  
Dependent Manner ◽  
Tyrosine Kinase Activity ◽  
Abl Tyrosine Kinase ◽  
C Terminus

ABSTRACT BRCA1 plays an important role in mechanisms of response to double-strand breaks, participating in genome surveillance, DNA repair, and cell cycle checkpoint arrests. Here, we identify a constitutive BRCA1-c-Abl complex and provide evidence for a direct interaction between the PXXP motif in the C terminus of BRCA1 and the SH3 domain of c-Abl. Following exposure to ionizing radiation (IR), the BRCA1-c-Abl complex is disrupted in an ATM-dependent manner, which correlates temporally with ATM-dependent phosphorylation of BRCA1 and ATM-dependent enhancement of the tyrosine kinase activity of c-Abl. The BRCA1-c-Abl interaction is affected by radiation-induced modification to both BRCA1 and c-Abl. We show that the C terminus of BRCA1 is phosphorylated by c-Abl in vitro. In vivo, BRCA1 is phosphorylated at tyrosine residues in an ATM-dependent, radiation-dependent manner. Tyrosine phosphorylation of BRCA1, however, is not required for the disruption of the BRCA1-c-Abl complex. BRCA1-mutated cells exhibit constitutively high c-Abl kinase activity that is not further increased on exposure to IR. We suggest a model in which BRCA1 acts in concert with ATM to regulate c-Abl tyrosine kinase activity.

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