Figure 2

The N-terminal domain of HspX is necessary but not sufficient for its polar localization. (a) Fluorescence microscopy of M. smegmatis-∆hspX expressing either full-length HspX-GFP (HspX-GFP) or HspX-GFP missing the N-terminal 35 amino acids (∆N35-HspX-GFP). Images representative of >140 cells analyzed. (b) Cartoon representing analysis of relative polar vs. non-polar localization of green fluorescence in cells imaged in (a) – upper panel. Box and whisker plot of images analyzed according to the schematic (lower panel). Box represents inter-quartile range, with line representing median, and whiskers represent 95% confidence intervals. ***p < 0.001 by two-tailed Student’s t-test. (c) Analysis of green channel fluorescence intensity from HspX-GFP or ∆N35-HspX-GFP across the normalized cell length of images represented in (a), the symbol (n) represents number of individual cells analyzed. (d) Fluorescence microscopy of M. smegmatis-∆hspX expressing combinations of mCherry or GFP tagged full-length or truncated constructs of HspX as per the legend. (e) Cartoon schematic of model representing polar localization of oligomeric HspX. Full-length HspX can rescue the polar localization defect of ∆N35-HspX, presumably via formation of hetero-oligomers that are competent for trafficking to the pole.