DOI: 10.5281/zenodo.15465212
title: Periodic Obstacles Regulate Membrane Tension Propagation to Enable Localized Mechanotransduction

description: Numerical Source.zip: DVA.csv + TRNs.zip

Contains the numerical source data to construct the figures in Catala-Castro, BioRxiv, 2025 derived from analysing the active and the passive tether in a dual-trap tension propagation experiment. Content is derived from fitting the individual force-time traces to extract numerical values as described in the text. Data is organized in csv according to cell type and treatment with column header describing the content of the replications.




Column name
Description


name
Name of the file in the raw data


D (um)
tether separation


active peak (pN)
peak force (F_peak) of the active tether


passive peak (pN)
peak force (F_peak) of the passive tether


resting active (pN)
plateau force (F_static) of the active tether


resting passive (pN)
plateau force (F_static) of the passive tether


peak (%)
Ratio of the peak force (passive/active)


resting (%)
Ratio of the plateau force (passive/active)


delay (s)
Temporal lag between the peaks of the active and the passive tether


base active (pN)
Baseline, resting force (F_rest) of the active tether


base passive (pN)
Baseline, resting force (F_rest) of the passive tether




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The zip-folder Raw-data.zip contains all raw force-time data derived from a dual optical trapping experiment to measure membrane tension propagation along the neurites of cultured primary C elegans neurons. The data is extensive documented and described in the accompanying axonal_dual-trap.docx document. Each condition can be found in a subfolder with individual pulling trajectories aligned and sorted within. 
description: The zip file of the raw-data contains the following results derived from strains and conditions:

in additoin, the sip folder contains also a docx file with the explanation and rational behind using these conditions.

The conditions testes are summarized in this table:

                   




Neuron type



strain



name



Label



drug



N neurons



N pulls



TARGET / RATIONALE







TRN



WT



GN692



dt



control



40



108



actin cytoskeleton





lat



Lat-A 0.5 uM



11



32





lat



Lat-A 1 uM



10



34





lat



Lat-A 10 uM



18



67





lat



Lat-A 1 uM o/n



9



35





cd



Cyto-D 2 uM



10



39





cd



Cyto-D 2 uM o/n



12



43







TRN



unc-70 (0): b-spectrin



MSB1176



trin



 



11



87



spectrin







TRN



mec-12: MT KO



GN510



mt



 



10



31



microtubules





mtzol



Noc 150 nM



7



30







TRN



mec-2 KO



MSB537



mec2ko



 



20



64



Channels. DVA has a different set of channels and MT protofilaments than TRN





DVA



WT



MSB273



dva



 



25



75







TRN



 WT



GN692



cydext



mbcD (3 mM)



11



40



Lipid membrane





cydext



mbcD (10 mM)



10



46





fat-3



MSB1099



fat



 



18



52





 WT



GN692



hypo



hypoosmotic



15



64





Table1. Summary of the conditions tested. TRN: Touch receptor neurons (there are 6 in C elegans). These neurons are the responsible for the worm’s sense of touch, they transduce a mechanical insult into a bioelectrical current. DVA: This single neuron, which lays at the ventral side of the worm, senses the body curvature so it gives the animal a sense of proprioception during locomotion/crawling. Lat-A: latrunculin A; Cyto-D: Cytochalasin D; Noc: nocodazole; mbcD: methyl-beta-cyclodextrin

DATA ACQUISITION

Optical force signals are acquired using our optical trap system (Sensocell, Impetux Optics). I name the data as nameXa, where name is the strain/condition tested, X is the neuron numerical ID, and a identifies the pulling event. For example, this is dt46, i.e. the 46th cell I tried in control conditions, and dt46a, ..., dt46d are the 4 pulls at different distances. Pulls a, ..., d don’t have to be necessarily ordered at increasing distances along the axon. I uploaded two types of signals on our shared folder on One Drive (I’m using neuron dt46 as an example):





dt46_DualTrapTrace.mat: this is the raw data directly obtained from the experiment. fx1, fx2, fy1 and fy2 are the force signals (pN) along the x and y directions for trap 1 and 2, respectively; p1 and p2 are the power signals (mW); x1, x2, y1 and y2 are the trap coordinates; t1 and t2 are the time points (s). The latter will be spaced 80 ms and interleaved at 40 ms, because we are using the time-sharing mode of an AOD-driven optical trapping set-up with two traps. Very briefly, the time-sharing mode means that the trap position is switched from trap 1 to trap 2 very fast, at 25 kHz (1/40 ms), so fast that the trapped bead feels a quasistatic potential.





dt46_DualTrapForce.fig is a figure showing the raw data. Pulls a, ..., d, transverse to the axon, are indicated as shadowed areas. These are the pulls I pick out for the next MAT file and figures.







Raw data. The workspace snapshot shows all the variables in dt46_DualTrapTrace.mat. In this example, all the pulls are horizontal because the axon is vertical. In the X panel, you can see the change in the separation between the two traps. I show a sketch of the field of view to explain that there is a change in the sign in the trap coordinate, but not on the force signals. This is not important because I adapt the raw data to the aligned files explained later. 





dt46a_aligned.mat, ..., dt46d_aligned.mat: Chopped signals for each of the pulls. All the pulls are applied at 40 mm/s and are followed by 5 s of relaxation. After that, the trap goes back to the initial point at 40 mm/s and waits. After 5 s, the pull is applied with the other trap, but this data is not analyzed.



Variables:







active: which of whether trap 1 or 2 is the active in this pull




DTD: dual tether distance. When the axon is straight and parallel to either axis, this is equal to the distance between the traps, but I do this measurement manually if the axon is curved.




fa: force signal of the active trap




fp: force signal of the passive trap




posa: trap position signal of the active trap




posp: trap position signal of the passive trap




t: time. Ideally, this should be equi-spaced points at 80 us, but might vary due to the electronics of the optical trap set-up




fm_ative: direction of the active trap trajectory. 1: X; 2: Y




fm_passive: direction of the passive trap trajectory




forcesigna: whether I changed the sign of the force signal for convenience, I mean peak upwards and relaxation downwards. This is for the active trap




forcesignp: This is the same, for the passive trap.




Figure:







dt46_all4.fig: summary of the neuron. The pulls here are ordered at increasing dual trap distance (DTD)