Regulation of KIF1A motility via polyglutamylation of tubulin C-terminal tails

Abstract

Axonal transport is a highly regulated cellular process responsible for site-specific neuronal cargo delivery. This process is mediated in part by KIF1A, a member of the kinesin-3 family of molecular motors. It is imperative that KIF1A's highly efficient, superprocessive motility along microtubules is tightly regulated as misregulation of KIF1A cargo delivery is observed in many neurodegenerative diseases. However, the regulatory mechanisms responsible for KIF1A's motility, and subsequent proper spatiotemporal cargo delivery, are largely unknown. One potential regulatory mechanism of KIF1A motility is through the posttranslational modifications (PTMs) of axonal microtubules. These PTMs, often occurring on the C-terminal tails of the microtubule tracks, act as molecular "traffic signals" helping to direct kinesin motor cargo delivery. Occurring on neuronal microtubules, C-terminal tail polygutamylation is known to be important for KIF1A cargo transport. KIF1A's initial interaction with microtubule C-terminal tails is facilitated by the K-loop, a positively charged surface loop of the KIF1A motor domain. However, the K-loop's role in KIF1A motility and response to perturbations in C-terminal tail polyglutamylation is underexplored. Using single-molecule imaging, we present evidence of KIF1A's previously unreported pausing behavior on multiple microtubule structures. Further analysis revealed that these pauses link multiple processive segments together, contributing to KIF1A's characteristic superprocessive run length. We further demonstrate that KIF1A pausing is mediated by a Kloop/polyglutamylated C-terminal tail interaction and is a regulatory mechanism of KIF1A motility. In summary, we introduce a new mechanism of KIF1A motility regulation, providing further insight into KIF1A's role in axonal transport.

Axonal transport during injury on a theoretical axon

“…To incorporate asymmetric coupling with MTs Kolomeisky, 2004, 2006;Jiang et al, 2007Jiang et al, , 2008Xiao et al, 2010), we used a three-MT MMLS and lateral movement parameters introduced for both kinesins to regulate crowding dynamics (Figure 1C). Two neuronal kinesins, Kin1 (S) and Kin3 (F) are described in the text, chosen for their significance and differences in motility and processivity (Verbrugge et al, 2009;Sun et al, 2011;Soppina et al, 2014;Lessard et al, 2019). LK detachment/reattachment dynamics (Jiang et al, 2007;Wang et al, 2007;Vuijk et al, 2015) are evaluated relative to kinesin-specific parameters and MMLS interactions.…”

“…DyNAMO provides multiple types of quantifiable readings resulting from MT injury for the motor types navigating the theoretical axon, including input, stalling, progression patterns, and outputs. The roles and impact of varying kinesin types and their motility parameters in in vivo axon transport (Brunner et al, 2004;Verbrugge et al, 2009;Lo et al, 2011;Sun et al, 2011;Jenkins et al, 2012;Lessard et al, 2019), including axonal distribution (Hirokawa et al, 2009), remain unknown. Advanced theoretical axon models, such as DyNAMO, will benefit the understanding of axonal mechanisms and aid the analysis of brain injury pathologies and axonopathies that impact axonal MT structure and neuronal signaling.…”

TUBB3 and KIF21A in neurodevelopment and disease

“…Removing either the terminal lysine or polyglutamylation of the TUBB3 C-terminal tail restored KIF5B run length to that of TUBB2B (Sirajuddin et al, 2014). Similarly, KIF1A interacted with TUBB3 C-terminal tail, and polyglutamylation of TUBB3 reduced KIF1A pausing and increased its landing rate and run length (Lessard et al, 2019).…”

Selective regulation of kinesin-5 function by β-tubulin carboxy-terminal tails

“…Consistent with this notion, microtubule motors do not respond uniformly to changes in CTTs: motors exhibit differential effects on velocity and processivity when measured on microtubules with engineered isotype CTT sequences and modification state (Sirajuddin et al, 2014). Furthermore, kinesin-3 landing rate and motility differs depending on the source of the mammalian tubulin, potentially as a result of differences in isotype composition or polyglutamylation state, and kinesin-1 processivity is affected by polyglutamylation state (Genova et al, 2023;Lessard et al, 2019). However, determining what motors are sensitive to the CTTs and the molecular basis of these interactions remains a major question.…”