Figure 1. Piezo2 is restricted to axonal endings across morphologically dissimilar Aβ RA-LTMRs.

(A) Image of three main skin/tissue regions that contain end organs formed by Aβ RA-LTMRs: lanceolate endings around hair follicles, Meissner corpuscles within glabrous skin of digit tips and pedal pads (regions indicated in pink), and Pacinian corpuscles (indicated by the PLP^EGFP fluorescent label) around the periosteum of the fibula. Diagrams illustrate end organs with Aβ RA-LTMRs in magenta. Representative confocal images show Aβ RA-LTMRs (NFH⁺) and specialized non-neuronal Schwann cells (S100B⁺) of each end organ. Dashed lines outline the hair follicle (left), dermal papilla (middle), and boundary of outer and inner core (right). Scalebar, 20 μm.

(B) Top, schematic diagram of the Piezo2^smFP-FLAG allele. Bottom, confocal images of Piezo2-FLAG localization to Aβ RA-LTMR axons (NFH⁺) in the three end organs. Red arrowheads indicate co-localized FLAG and NFH signal. Blue arrowheads indicate axonal NFH signal outside the end organ that lacks FLAG signal. This experiment was repeated in two animals with littermate controls. Scalebar, 25 μm.

(C) Immuno-electron micrographs from a Piezo2^smFP-FLAG animal stained for FLAG with silver enhancement show localization of the Piezo2-FLAG fusion protein along the membranes of Aβ RA-LTMRs (pseudo-colored pink). Pink arrowheads indicate a subset of Piezo2-FLAG puncta along sensory axon membranes; green arrowheads indicate a subset of puncta along axon protrusions. Piezo2-FLAG is also localized to the membrane of Aβ field-LTMR circumferential endings around the guard hair (blue). This experiment was repeated in two animals with littermate controls. Scalebar, 1 μm.

(D) Same as in (C) but for wild-type littermate of the Piezo2^smFP-FLAG animal. See also Figures S1–S2.