Biology subjects

McCaughey, J.

Publications and source records attributed to McCaughey, J..

4 recordsLinked to original sources

bioRxiv2022

Axonal ER tubules regulate local translation via P180/RRBP1-mediated ribosome interactions

Local mRNA translation in axons is critical for the spatial and temporal regulation of the axonal proteome. A wide variety of mRNAs are localized and translated in axons, however how protein synthesis is regulated at specific subcellular sites in axons remains unclear. Here, we establish that the axonal endoplasmic reticulum (ER) supports axonal translation. Axonal ER tubule disruption impairs local translation and ribosome distribution. Using nanoscale resolution imaging, we find that ribosomes make frequent contacts with ER tubules in the axon in a translation-dependent manner and are influenced by specific extrinsic cues. We identify P180/RRBP1 as an axonally distributed ribosome receptor that regulates local translation in an mRNA-dependent manner. Our results establish an important role for the axonal ER in localizing mRNA translation and in dynamically regulating the axonal proteome in response to neuronal stimuli.

neuroscience↗

bioRxiv2021

MIA3/TANGO1 enables efficient secretion by constraining COPII vesicle budding

Complex machinery is required to drive secretory cargo export from the endoplasmic reticulum, an essential process in eukaryotic cells. In vertebrates, the Mia3 gene encodes two major forms of Transport ANd Golgi Organization Protein 1 (TANGO1S and TANGO1L). Here, using genome engineering of human cells, light microscopy, secretion assays, genomics, and proteomics we show that disruption of the longer form, TANGO1L, results in relatively minor defects in secretory pathway organization and function including limited impacts on procollagen secretion. In contrast, loss of both long and short forms results in major defects in cell organization and secretion. These include a failure to maintain the localization of ERGIC53 and SURF4 to the ER-Golgi Intermediate Compartment and dramatic changes to the ultrastructure of the ER-Golgi interface. Disruption of TANGO1 expression also causes significant changes in early secretory pathway gene and protein expression. Disruption of both TANGO1L and TANGO1S expression impairs secretion not only of large proteins, including procollagens, but of all types of secretory cargo including small soluble proteins. Our data support a general role for Mia3/TANGO1 in maintaining both secretory pathway structure and function in vertebrate cells.

cell biology↗

bioRxiv2018

ER-to-Golgi trafficking of procollagen in the absence of large carriers.

Secretion and assembly of collagen is fundamental to the function of the extracellular matrix. Defects in the assembly of a collagen matrix lead to pathologies including fibrosis and osteogenesis imperfecta. Owing to the size of fibril-forming procollagen molecules it is assumed that they are transported from the endoplasmic reticulum to the Golgi in specialised large COPII-dependent carriers. Here, analysing endogenous procollagen and a new engineered GFP-tagged form, we show that transport to the Golgi occurs in the absence of large carriers. Large GFP-positive structures are observed occasionally but these are non-dynamic, are not COPII-positive, and label with markers of the ER. We propose a \"short-loop\" model of COPII-dependent ER-to-Golgi traffic that, while consistent with models of ERGIC-dependent expansion of COPII carriers, does not invoke long-range trafficking of large vesicular structures. Our findings provide an important insight into the process of procollagen trafficking and reveal a short-loop pathway from the ER to the Golgi, without the use of large carriers.\n\nSummaryTrafficking of procollagen is essential for normal cell function. Here, imaging of GFP-tagged type I procollagen reveals that it is transported from the endoplasmic reticulum to the Golgi, without the use of large carriers.

cell biology↗

bioRxiv2017

Regulator of calcineurin-2 is a ciliary protein with a role in cilia length control.

Almost every cell in the human body extends a primary cilium. Defective cilia function leads to a set of disorders known as ciliopathies characterised by debilitating developmental defects affecting many tissues. Here we report a new role for regulator of calcineurin 2, RCAN2, in primary cilia function. It localises to centrioles and the basal body and is required to maintain normal cilia length. RCAN2 was identified as the most strongly upregulated gene from a comparative RNAseq analysis of cells in which expression of the Golgi matrix protein giantin had been abolished by gene editing. In contrast to previous work where we showed that depletion of giantin by RNAi results in defects in ciliogenesis and in cilia length control, giantin knockout cells generate normal cilia on serum withdrawal. Furthermore, giantin knockout zebrafish show increased expression of RCAN2. Importantly, suppression of RCAN2 expression in giantin knockout cells results in the same defects in cilia length control seen on RNAi of giantin itself. Together these data define RCAN2 as a regulator of cilia function that can compensate for loss of giantin function.

cell biology↗