The yeast Wsc1 cell surface sensor behaves like a nanospring in vivo

Abstract

Here we report on in vivo measurement of the mechanical behavior of a cell surface sensor using single-molecule atomic force microscopy. We focus on the yeast wall stress component sensor Wsc1, a plasma membrane protein that is thought to function as a rigid probe of the cell wall status. We first map the distribution of individual histidine-tagged sensors on living yeast cells by scanning the cell surface with atomic force microscopy tips carrying nitrilotriacetate groups. We then show that Wsc1 behaves like a linear nanospring that is capable of resisting high mechanical force and of responding to cell surface stress. Both a genomic pmt4 deletion and the insertion of a stretch of glycines in Wsc1 result in substantial alterations in protein spring properties, supporting the important role of glycosylation at the extracellular serine/threonine-rich region.

Regulation of Cell Wall Biogenesis in Saccharomyces cerevisiae: The Cell Wall Integrity Signaling Pathway

“…Therefore, these proteins have been proposed to function as mechanosensors that act as rigid probes of the extracellular matrix (Rajavel et al 1999;Philip and Levin 2001). A recent study using atomic force microscopy to probe the physical characteristics of Wsc1 supports this conclusion and suggests that this sensor behaves as a linear nanospring (Dupres et al 2009). …”

Together we are strong—cell wall integrity sensors in yeasts

“…The induced conformational changes could then be transmitted to the cytoplasmic tails, allowing the intracellular response to be triggered. Several observations support this hypothesis: (a) drugs affecting either the cell wall polysaccharide composition (such as Calcofluor white and Congo red) or the plasma membrane (such as chlorpromazine or tea tree oil) have been shown to activate the CWI pathway [50]; (b) mutants with a defective O-mannosylation of the sensors (and of other secreted cell wall proteins) display the typical cell lysis phenotypes of CWI pathway mutants [32]; (c) biophysical evidence from determination of the mechanics of single molecules measured in vivo by atomic force microscopy (AFM) suggests that the STR region confers a nanospring structure to the Wsc1 sensor, consistent with a rigid connection between the TMD and the CRD [9]. In fact, the authors found that a lower degree of mannosylation or the insertion of non-mannosylated glycine residues within the STR region abolished the nanospring properties.…”

“…It should be noted that the cell wall of K. lactis is considerably thinner than that of S. cerevisiae for cells growing on glucose [1], indicating that the head groups of the sensors will be closer to the surface than those of their homologues in S. cerevisiae. Notably, the S. cerevisiae sensors differ significantly in the length of their extracellular regions, reaching out a maximum of 80, 110, 125, 70 and 115 nm for Wsc1, Wsc2, Wsc3, Mid2 and Mtl1, respectively (assuming a linear protein structure and a peptide bond length of 0.36 nm [9]). Presumably, the individual members of each type of sensor family (i.e.…”

Putative Stress Sensors WscA and WscB Are Involved in Hypo-Osmotic and Acidic pH Stress Tolerance in Aspergillus nidulans

“…A GFP fusion localization study revealed that Wsc1 resides in membrane patches within the plasma membrane in both S. cerevisiae and K. lactis (39,44). Recently, single-molecule atomic force microscopy revealed that Wsc1 behaves like a linear nanospring that is capable of resisting a high level of mechanical force and of responding to cell surface stress (6). The WSC domain of Wsc1 is required for clustering stimulated by stressful conditions (16).…”