A kinesin adapter directly mediates dendritic mRNA localization during neural development in mice

Abstract

Motor protein-based active transport is essential for mRNA localization and local translation in animal cells, yet how mRNA granules interact with motor proteins remains poorly understood. Using an unbiased yeast two–hybrid screen for interactions between murine RNA-binding proteins (RBPs) and motor proteins, here we identified protein interaction with APP tail-1 (PAT1) as a potential direct adapter between zipcode-binding protein 1 (ZBP1, a β-actin RBP) and the kinesin-I motor complex. The amino acid sequence of mouse PAT1 is similar to that of the kinesin light chain (KLC), and we found that PAT1 binds to KLC directly. Studying PAT1 in mouse primary hippocampal neuronal cultures from both sexes and using structured illumination microscopic imaging of these neurons, we observed that brain-derived neurotrophic factor (BDNF) enhances co-localization of dendritic ZBP1 and PAT1 within granules that also contain kinesin-I. PAT1 is essential for BDNF-stimulated neuronal growth cone development and dendritic protrusion formation, and we noted that ZBP1 and PAT1 co-locate along with β-actin mRNA in actively transported granules in living neurons. Acute disruption of the PAT1–ZBP1 interaction in neurons with PAT1 siRNA or a dominant-negative ZBP1 construct diminished localization of β-actin mRNA but not of Ca2+/calmodulin-dependent protein kinase IIα (CaMKIIα) mRNA in dendrites. The aberrant β-actin mRNA localization resulted in abnormal dendritic protrusions and growth cone dynamics. These results suggest a critical role for PAT1 in BDNF-induced β-actin mRNA transport during postnatal development and reveal a new molecular mechanism for mRNA localization in vertebrates.

Microtubule-based Transport is Essential to Distribute RNA and Nascent Protein in Skeletal Muscle

“…In neurons, RNPs are actively transported along microtubules by the motor proteins kinesin and dynein, and these interactions are mediated by protein-based (Baumann et al, 2020; Dictenberg et al, 2008; Wu et al, 2020) or vesicular adaptors (Cioni et al, 2019; Liao et al, 2019). Properly regulated microtubule-based RNP transport and local translation are important to prevent neurological disease, which is often caused by mutations to microtubule associated proteins (Deniston et al, 2020; Dubey et al, 2015), motor proteins and adaptors (Hirokawa et al, 2010; Liao et al, 2019; Nicolas et al, 2018; Zhao et al, 2001), RBPs (Fernandopulle et al, 2021; Ramaswami et al, 2013), and regulators of translation (Banerjee et al, 2018; Kapur et al, 2017).…”

The Coordination of Local Translation, Membranous Organelle Trafficking, and Synaptic Plasticity in Neurons

“…RBPs within the granule can interact with the motors either directly or via adaptor proteins (Figure 2; Kanai et al, 2004;Hirokawa, 2006;Kiebler and Bassell, 2006;Davidovic et al, 2007;Dictenberg et al, 2008). Transport of mRNAs that encode the key plasticity proteins, such as CaMKII (CaMKIIa) and β-Actin (ActB), occurs via this mechanism on microtubule tracks (Tiruchinapalli et al, 2003;Mikl et al, 2011;Wu et al, 2020). In contrast, short-range trafficking of RNA granules is mediated by myosin motors on F-actin filaments (Figure 2).…”

“…To support this notion, Liao et al (2019) observed the LAMP1-ANXA11 association in dendrites in addition to axons, hinting that lysosomal hitchhiking for long-range transport could also exist in the dendritic arbor. Other outstanding questions include how a particular transport strategy is selected: β-actin mRNA is trafficked by both conventional trafficking mechanisms and vesicular hitchhiking (Liao et al, 2019;Wu et al, 2020), suggesting that a given mRNA could be transported by either mode of transport. Understanding under what physiological circumstances (e.g., certain types of plasticity, cell stress) these transport itineraries are selected will be imperative to fully define the process of RNA granule trafficking to synapses.…”

A Picture Worth a Thousand Molecules—Integrative Technologies for Mapping Subcellular Molecular Organization and Plasticity in Developing Circuits

“…Microdissection and TRAP approaches for isolating RNA have revealed important roles for transcript UTR sequence motifs and transcript trafficking proteins in local translation. mRNAs are transported in phase-separated ribonucleoprotein (RNP) granules over long distances to dendrites and axons to establish local transcriptome pools (Nalavadi et al, 2012;Jung et al, 2014;Das et al, 2019;Liao et al, 2019;Pushpalatha and Besse, 2019;Fukuda et al, 2020;Rhine et al, 2020;Wu et al, 2020; Figure 3). The spatial control of transcript trafficking is based on mRNA sequences found in 3 and 5 untranslated regions (UTRs; Figure 3A) that act as binding sites for trans-acting RBPs (Sahoo et al, 2018;Bae and Miura, 2020).…”