Browsing by Author "Kaplan, Oktay Ismail"

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CilioGenics: an integrated method and database for predicting novel ciliary genes
(Oxford University Press, 2024) Pir, Mustafa Samet; Begar, Efe; Yenisert, Ferhan; Demirci, Hasan C.; Korkmaz, Mustafa E.; Karaman, Asli; Tsiropoulou, Sofia; Firat-Karalar, Elif Nur; Blacque, Oliver E.; Oner, Sukru S.; Doluca, Osman; Cevik, Sebiha; Kaplan, Oktay Ismail; 0000-0002-4645-7626; 0000-0002-0935-1929; 0000-0002-8733-0920; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Moleküler Biyoloji ve Genetik Bölümü; Pir, Mustafa Samet; Yenisert, Ferhan; Demirci, Hasan C.; Korkmaz, Mustafa E.; Cevik, Sebiha; Kaplan, Oktay Ismail
Uncovering the full list of human ciliary genes holds enormous promise for the diagnosis of cilia-related human diseases, collectively known as ciliopathies. Currently, genetic diagnoses of many ciliopathies remain incomplete (1–3). While various independent approaches theoretically have the potential to reveal the entire list of ciliary genes, approximately 30% of the genes on the ciliary gene list still stand as ciliary candidates (4,5). These methods, however, have mainly relied on a single strategy to uncover ciliary candidate genes, making the categorization challenging due to variations in quality and distinct capabilities demonstrated by different methodologies. Here, we develop a method called CilioGenics that combines several methodologies (single-cell RNA sequencing, protein-protein interactions (PPIs), comparative genomics, transcription factor (TF) network analysis, and text mining) to predict the ciliary capacity of each human gene. Our combined approach provides a CilioGenics score for every human gene that represents the probability that it will become a ciliary gene. Compared to methods that rely on a single method, CilioGenics performs better in its capacity to predict ciliary genes. Our top 500 gene list includes 258 new ciliary candidates, with 31 validated experimentally by us and others. Users may explore the whole list of human genes and CilioGenics scores on the CilioGenics database (https://ciliogenics.com /).
Environmental responsiveness of tubulin glutamylation in sensory cilia is regulated by the p38 MAPK pathway
(NATURE PUBLISHING GROUP, MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND, 2018) Kimura, Yoshishige; Tsutsumi, Koji; Konno, Alu; Ikegami, Koji; Hameed, Saira; Kaneko, Tomomi; Kaplan, Oktay Ismail; Teramoto, Takayuki; Fujiwara, Manabi; Ishihara, Takeshi; Blacque, Oliver E.; Setou, Mitsutoshi; AGÜ, Yaşam ve Doğa Bilimleri Fakültesi, Biyomühendislik Bölümü;
Glutamylation is a post-translational modification found on tubulin that can alter the interaction between microtubules (MTs) and associated proteins. The molecular mechanisms regulating tubulin glutamylation in response to the environment are not well understood. Here, we show that in the sensory cilia of Caenorhabditis elegans, tubulin glutamylation is upregulated in response to various signals such as temperature, osmolality, and dietary conditions. Similarly, tubulin glutamylation is modified in mammalian photoreceptor cells following light adaptation. A tubulin glutamate ligase gene ttll-4, which is essential for tubulin glutamylation of axonemal MTs in sensory cilia, is activated by p38 MAPK. Amino acid substitution of TTLL-4 has revealed that a Thr residue (a putative MAPKphosphorylation site) is required for enhancement of tubulin glutamylation. Intraflagellar transport (IFT), a bidirectional trafficking system specifically observed along axonemal MTs, is required for the formation, maintenance, and function of sensory cilia. Measurement of the velocity of IFT particles revealed that starvation accelerates IFT, which was also dependent on the Thr residue of TTLL-4. Similarly, starvation-induced attenuation of avoidance behaviour from high osmolality conditions was also dependent on ttll-4. Our data suggest that a novel evolutionarily conserved regulatory system exists for tubulin glutamylation in sensory cilia in response to the environment.