PT  - JOURNAL ARTICLE
AU  - Anil Kumar Ganga
AU  - Margaret C. Kennedy
AU  - Mai E. Oguchi
AU  - Shawn D. Gray
AU  - Kendall E. Oliver
AU  - Tracy A. Knight
AU  - Enrique M. De La Cruz
AU  - Yuta Homma
AU  - Mitsunori Fukuda
AU  - David K. Breslow
TI  - Rab34 GTPase mediates ciliary membrane biogenesis in the intracellular ciliogenesis pathway
AID  - 10.1101/2020.10.29.360891
DP  - 2020 Jan 01
TA  - bioRxiv
PG  - 2020.10.29.360891
4099  - http://biorxiv.org/content/early/2020/10/29/2020.10.29.360891.short
4100  - http://biorxiv.org/content/early/2020/10/29/2020.10.29.360891.full
AB  - Primary cilia form by two pathways: an extracellular pathway in which the cilium grows out from the cell surface and an intracellular pathway in which the nascent cilium forms inside the cell. Here we identify the GTPase Rab34 as a selective mediator of intracellular ciliogenesis. We find that Rab34 is required for formation of the ciliary vesicle at the mother centriole and that Rab34 marks the ciliary sheath, a unique sub-domain of assembling intracellular cilia. Rab34 activity is modulated by divergent residues within its GTPase domain, and ciliogenesis requires GTP binding and turnover by Rab34. Because Rab34 is found on assembly intermediates that are unique to intracellular ciliogenesis, we tested its role in the extracellular pathway used by MDCK cells. Consistent with Rab34 acting specifically in the intracellular pathway, MDCK cells ciliate independently of Rab34 and paralog Rab36. Together, these findings reveal a new context-specific molecular requirement for ciliary membrane biogenesis.Competing Interest StatementThe authors have declared no competing interest.cytoDcytochalasin DDAVDistal appendage vesicleFIB-SEMFocused ion beam scanning electron microscopyGAPGTPase activating proteinGEFGuanine nucleotide exchange factorHhHedgehogLAPLocalization and affinity purification tag (containing GFP, TEV protease site, and S-tag)NbNanobodyGEFGuanine nucleotide exchange factorpolyE-tubpolyglutamylated tubulinsgRNAsingle guide RNASIMStructured illumination microscopy