Post-translational polymodification of β1-tubulin regulates motor protein localization in platelet production and function

Khan, AO; Slater, A; Maclachlan, A; Nicolson, PLR; Pike, JA; Reyat, JS; Yule, J; Stapley, R; Rayes, J; Thomas, SG; Morgan, NV

Journal article

Post-translational polymodification of β1-tubulin regulates motor protein localization in platelet production and function

Abstract:: Germline defects affecting the DNA-binding domain of the transcription factor FLI1 are associated with a bleeding disorder that is characterised by the presence of large, fused α-granules in platelets. We investigated whether the genes showing abnormal expression in FLI1-deficient platelets could be involved in platelet α-granule biogenesis by undertaking transcriptome analysis of control platelets and platelets harbouring a DNA-binding variant of FLI1. Our analysis identified 2276 transcripts that were differentially expressed in FLI1- deficient platelets. Functional annotation clustering of the coding transcripts revealed significant enrichment for gene annotations relating to protein transport, and identified Sorting nexin 24 (SNX24) as a candidate for further investigation. Using an iPSC-derived megakaryocyte model, SNX24 expression was found to be increased during the early stages of megakaryocyte differentiation and downregulated during proplatelet formation, indicating tight regulatory control during megakaryopoiesis. CRISPR-Cas9 mediated knockout (KO) of SNX24 led to decreased expression of immature megakaryocyte markers, CD41 and CD61, and increased expression of the mature megakaryocyte marker CD42b (p=0.0001), without affecting megakaryocyte polyploidisation, or proplatelet formation. Electron microscopic analysis revealed an increase in empty membrane-bound organelles in SNX24 KO megakaryocytes, a reduction in α-granules and an absence of immature and mature multivesicular bodies, consistent with a defect in the intermediate stage of α-granule maturation. Co-localisation studies showed that SNX24 associates with each compartment of α-granule maturation. Reduced expression of CD62P and VWF was observed in SNX24 KO megakaryocytes. We conclude that SNX24 is required for α-granule biogenesis and intracellular trafficking of α-granule cargo within megakaryocytes

Publication status:: Published

Peer review status:: Peer reviewed

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APA Style

Khan, A. O., Slater, A., Maclachlan, A., Nicolson, P. L. R., Pike, J. A., Reyat, J. S., Yule, J., Stapley, R., Rayes, J., Thomas, S. G., & Morgan, N. V. (2020). Post-translational polymodification of β1-tubulin regulates motor protein localization in platelet production and function. Haematologica, 107(1), 243–259.

MLA Style

Khan, AO, et al. “Post-Translational Polymodification of β1-Tubulin Regulates Motor Protein Localization in Platelet Production and Function.” Haematologica, vol. 107, no. 1, 2020, pp. 243–59.

Chicago Style

Khan, AO, A Slater, A Maclachlan, et al. 2020. “Post-Translational Polymodification of β1-Tubulin Regulates Motor Protein Localization in Platelet Production and Function.” Haematologica 107 (1): 243–59.
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