Publications by authors named "Koray Kırımtay"

In this study, we aimed to determine the genetic basis of a Turkish family related to hereditary spastic paraplegia (HSP) by exome sequencing. HSP is a progressive neurodegenerative disorder and displays genetic and clinical heterogeneity. The major symptoms are muscle weakness and spasticity, especially in the lower extremities.

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Background: Kufor-Rakeb Syndrome (KRS) is an autosomal recessive disease characterized by Parkinsonism, pyramidal signs, dementia, and supranuclear gaze palsy. KRS is caused by mutations in ATP13A2producing a transmembrane protein responsible for the regulation of intracellular inorganic cations.

Objective: Two siblings born to a Turkish family of consanguineous marriage had mixed neurological presentations with the presence of hypointense images on T2-weighted MRI and were pre-diagnosed as having autosomal recessive spastic paraparesis or ataxia.

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Tumor suppressor protein p53, which functions in the cell cycle, apoptosis and neuronal differentiation via transcriptional regulations of target genes or interactions with several proteins, has been associated with neurite outgrowth through microtubule re-organization. We previously demonstrated in neurons that upon p53 induction, the level of microtubule severing protein Katanin-p60 increases, indicating that p53 might be a transcriptional regulator of the KATNA1 gene encoding Katanin-p60. In this context, we firstly elucidated the activity of KATNA1 regulatory regions and endogenous KATNA1 mRNA levels in the presence or absence of p53 using HCT 116 WT and HCT 116 p53 (-/-) cells.

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Microtubule severing, which is highly critical for the survival of both mitotic and post-mitotic cells, has to be precisely adjusted by regulating the expression levels of severing proteins, katanin and spastin. Even though severing mechanism is relatively well-studied, there are limited studies for the transcriptional regulation of microtubule severing proteins. In this study, we identified the main regulatory region of KATNA1 gene encoding katanin-p60 as 5' UTR, which has a key role for its expression, and showed Elk1 binding to KATNA1.

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POC1A encodes a WD repeat protein localizing to centrioles and spindle poles and is associated with short stature, onychodysplasia, facial dysmorphism and hypotrichosis (SOFT) syndrome. These main features are related to the defect in cell proliferation of chondrocytes in growth plate. In the current study, we aimed at identifying the molecular basis of two patients with primordial dwarfism (PD) in a single family through utilization of whole-exome sequencing.

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Katanin is an ATPase family member protein that participates in microtubule severing. It has heterodimeric structure consisting of 60 kDa (katanin-p60) and 80 kDa (katanin-p80) subunits encoded by KATNA1 and KATNB1 genes, respectively. Katanin-p60 has the enzymatic activity for microtubule severing, whereas katanin-p80 consists of multiple domains with different functions such as targeting katanin-p60 to the centrosome, augmenting microtubule severing by katanin-p60, and even suppressing microtubule severing.

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The most common cause of autosomal dominant hereditary spastic paraplegia, that is characterized with axonal degeneration in corticospinal tracts and posterior columns, is known to be caused by mutations in the SPG4 gene which encodes spastin, a microtubule severing ATPase belonging to AAA family. Spastin promotes the formation of microtubule networks that are essential for axon growth and branching which are important for neuronal plasticity. Mutations observed in SPG4 gene of hereditary spastic paraplegia patients have been shown to cause reduced spastin levels.

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