Topic
Ciliary pocket membrane
About: Ciliary pocket membrane is a research topic. Over the lifetime, 3 publications have been published within this topic receiving 58 citations.
Papers
TL;DR: In this paper, the relative light and electron microscopy (CLEM) method was used for the determination of high-resolution structural information for proteins of interest within their biological context through the combination of electron and fluorescence microscopies.
Abstract: Correlative light and electron microscopy (CLEM) enables determination of high-resolution structural information for proteins of interest within their biological context through the combination of electron and fluorescence microscopies. Numerous electron microscopy (EM) studies of primary cilia have provided ultrastructural details about these antennal-like organelles that extend from the surface of the cell. The core structure of the cilium includes a microtubule-based axoneme, a basal body derived from the mother centriole, and the ciliary membrane, which is connected to the plasma membrane. The small GTPase Rab8 localizes to the ciliary membrane and is important for ciliogenesis, and Rab11 transports the Rab8 guanine nucleotide exchange factor (GEF) Rabin8 to the mother centriole to activate Rab8-dependent ciliary membrane growth. Some primary cilia have a ciliary pocket membrane (CPM) which is observed as an involution from the plasma membrane to the base of the cilia membrane. The Rab11- and Rab8-assocaited membrane trafficking regulator Eps15 Homology Domain-containing protein 1 (EHD1) and EHD3 also function in early stages of ciliogenesis; however, they localize to the CPM. These ciliary localizations of Rab8 and EHD1 can be resolved using CLEM with conventional fluorescence microscopy and transmission electron microscopy (TEM) imaging. Here, we describe in detail the protocol for this CLEM method applicable for ciliary proteins and proteins in other cellular organelles.
TL;DR: In this paper, the authors show that the remodeling and endocytosis of the ciliary pocket membrane are accelerated during ciliary resorption, which depends on phospho(T94)Tctex-1, actin, and dynamin.
Abstract: The primary cilium is a plasma membrane-protruding sensory organelle that undergoes regulated assembly and resorption. While the assembly process has been studied extensively, the cellular machinery that governs ciliary resorption is less well understood. Previous studies showed that the ciliary pocket membrane is an actin-rich, endocytosis-active periciliary subdomain. Furthermore, Tctex-1, originally identified as a cytoplasmic dynein light chain, has a dynein-independent role in ciliary resorption upon phosphorylation at Thr94. Here, we show that the remodeling and endocytosis of the ciliary pocket membrane are accelerated during ciliary resorption. This process depends on phospho(T94)Tctex-1, actin, and dynamin. Mechanistically, Tctex-1 physically and functionally interacts with the actin dynamics regulators annexin A2, Arp2/3 complex, and Cdc42. Phospho(T94)Tctex-1 is required for Cdc42 activation before the onset of ciliary resorption. Moreover, inhibiting clathrin-dependent endocytosis or suppressing Rab5GTPase on early endosomes effectively abrogates ciliary resorption. Taken together with the epistasis functional assays, our results support a model in which phospho(T94)Tctex-1-regulated actin polymerization and periciliary endocytosis play an active role in orchestrating the initial phase of ciliary resorption.
TL;DR: It is demonstrated in human cells and zebrafish that the F-BAR domain containing proteins PACSIN1 and -2 play an essential role in ciliogenesis, similar to their binding partner and membrane reorganizer EHD1.
Abstract: The intracellular ciliogenesis pathway requires membrane trafficking, fusion, and reorganization. Here, we demonstrate in human cells and zebrafish that the F-BAR domain containing proteins PACSIN1 and -2 play an essential role in ciliogenesis, similar to their binding partner and membrane reorganizer EHD1. In mature cilia, PACSINs and EHDs are dynamically localized to the ciliary pocket membrane (CPM) and transported away from this structure on membrane tubules along with proteins that exit the cilium. PACSINs function early in ciliogenesis at the ciliary vesicle (CV) stage to promote mother centriole to basal body transition. Remarkably, we show that PACSIN1 and EHD1 assemble membrane tubules from the developing intracellular cilium that attach to the plasma membrane, creating an extracellular membrane channel (EMC) to the outside of the cell. PACSIN proteins are known to mediate membrane tubulation. Here the authors show that PACSIN - positive membranous tubules extend from the ciliary pocket membrane and during ciliogenesis from the ciliary vesicle to the plasma membrane, called extracellular membrane channels (EMCs).
Related Topics (5)
Performance Metrics
| Year | Papers |
|---|---|
| 2021 | 1 |
| 2019 | 1 |
| 2017 | 1 |