Biology subjects

Sadeghian, F.

Publications and source records attributed to Sadeghian, F..

3 recordsLinked to original sources

bioRxiv2026

PES-8 is required for Cytoskeletal Organization and Contractility in the C. elegans Spermatheca

Proper regulation of contraction and relaxation in biological tubes is essential for organismal function. In C. elegans, the spermatheca, composed of smooth muscle-like cells, undergoes repeated stretching and contraction as oocytes pass through. Here we describe PES-8, a previously uncharacterized protein, as a regulator of spermatheca contractility. PES-8 contains a predicted extracellular zona pellucida-like domain and an unstructured cytoplasmic tail, suggesting dual roles in extracellular and cytoplasmic signaling. PES-8 localizes to the plasma membrane of the spermatheca, the spermathecal-uterine valve, and uterus. Functional analysis shows that PES-8 is essential for spermathecal function; its loss disrupts actomyosin fiber alignment, FLN-1/filamin localization, apical junction organization, and Ca{superscript 2} signaling, preventing oocyte transit. These findings identify PES-8 as a key regulator of cytoskeletal organization and calcium-mediated contractility in the C. elegans spermatheca.

cell biology↗

bioRxiv2025

GOA-1 regulates spermathecal transits

G protein signaling regulates calcium dynamics and contractility in the C. elegans spermatheca. G protein-coupled receptors activate heterotrimeric G proteins, triggering downstream cascades, including the Gs-mediated activation of adenylyl cyclase and subsequent Protein Kinase A (PKA) activation. Our previous work identified GSA-1/Gs and PKA as key modulators of Ca2+ oscillations and tissue contractility within the C. elegans spermatheca. In this study, we show that the inhibitory Gi/o subunit GOA-1 regulates spermathecal transits. We employed TurboID proximity labeling and mass spectrometry to identify 16 candidate interactors of GOA-1. Depletion of these candidates by RNAi did not yield overt spermathecal transit defects.

cell biology↗

bioRxiv2024

Tensions on the actin cytoskeleton and apical cell junctions in the C. elegans spermatheca are influenced by spermathecal anatomy, ovulation state and activation of myosin

Cells generate mechanical forces mainly through myosin motor activity on the actin cytoskeleton. In C. elegans, actomyosin stress fibers drive contractility of the smooth muscle-like cells of the spermatheca, a distensible, tube-shaped tissue in the hermaphrodite reproductive system and the site of oocyte fertilization. Stretching of the spermathecal cells by oocyte entry triggers activation of the small GTPase Rho. In this study, we asked how forces are distributed in vivo using the spermatheca, and explored how this tissue responds to alterations in myosin activity. Using laser ablation, we show that the basal actomyosin fibers are under tension in the occupied spermatheca. Reducing actomyosin contractility by depletion of the phospholipase C-{varepsilon}/PLC-1 or non-muscle myosin II/NMY-1, leads to distended spermathecae occupied by one or more embryos, but does not alter tension on the basal actomyosin fibers. This suggests that much of the tension on the basal actin fibers in the occupied spermatheca is due to the presence of the embryo. However, activating myosin through depletion of the Rho GAP SPV-1 increases tension on the actomyosin fibers, consistent with earlier studies showing Rho drives spermathecal contractility. On the inner surface of the spermathecal tube, tension on the apical junctions is decreased by depletion of PLC-1 and NMY-1. Surprisingly, when basal contractility is increased through SPV-1 depletion, the tension on apical junctions also decreases, with the most significant effect on the junctions aligned in perpendicular to the axis of the spermatheca. This suggests tension on the outer basal surface may compress the apical side, and suggests the three-dimensional shape of the spermatheca plays a role in force distribution and contractility during ovulation.

cell biology↗