TipQAD: an automated tool for quantifying apical fluorescence dynamics in tip-growing cells

Cell polarity is a fundamental property essential for the function and development of all cellular organisms. Tip growth is an extreme form of polar growth requiring spatiotemporally dynamic but highly coordinated cellular activities. Quantification of these dynamic activities is important for the systematic study of the mechanisms controlling cell polarity, but an automated and unbiased method for analyzing and quantification of tip-growing cells has been missing. In this paper, we developed a computational model and an associated tool called TipQAD for quantifying the spatiotemporal dynamics of fluorescence protein (FP) labeled molecules or structures in tip-growing cells. This tool robustly and accurately measured the spatial distribution and temporal dynamics of FP-labeled proteins in the cytoplasm or the plasma membrane at the tip region of several types of tip-growing cells. We also demonstrated its ability to analyze data from FRAP experiments. In conclusion, this tool showed great potential for automated measurements of the spatiotemporal dynamics of fluorescent-labeled cellular molecules and structures.