preview

Gtp Lab Report

Good Essays
Open Document

\textbf{A positive feedback mechanism to maintain the polarity patch on the plasma membrane.} \textbf{(a)} Cdc42 exists as GTP-Cdc42 (ON state) or GDP-Cdc42 (OFF state). The GTP-Cdc42 indirectly converts neighboring GDP-CDC42 into GTP-Cdc42, which sets off a positive feedback loop. GTP-Cdc42 exists predominantly in the plasma membrane and diffuses very slowly while GDP-Cdc42 diffuses fast in the cytosol. Since one of the components (the scaffold protein Bem1) that goes into causing the positive feedback gets depleted, the patch of GTP-Cdc42 stops growing. \textbf{(b) and (c)} Actin cables deliver patches to dilute the polarity patch to make it wander.}
\end{figure}

\subsection*{The receptor cluster wanders due to vesicle delivery at the polarity …show more content…

First, I will image a labeled polarity patch protein in the two strains under a spinning disk confocal microscope. Then, I will track the movement of the labeled protein, and use this to estimate the diffusion constant of the wandering polarity patch. Finally, a comparison of diffusion constants of the patches between G\(\alpha\) mutants and wild-type cells will reveal a difference in patch wandering, if any. My preliminary data indicates the polarity patch in a G\(\alpha\) mutant wanders significantly more than cells with wild-type G\(\alpha\). But at a molecular level, what could G\(\alpha\) be doing to the polarity …show more content…

Bni1's phosphorylation may influence its ability to nucleate actin cables. Since vesicle delivery by actin cables motivates patch wandering, a Bni1 protein that can't be phosphorylated may demonstrate a significant difference in patch wandering, which I'll attempt to verify experimentally (the same way I do in prior experiments). This genetic perturbation can also be incorporated into the mathematical model by altering the frequency of actin cable formation in response to bound pheromone in an attempt to consolidate my experimental results.

\bibliographystyle{ieeetr}
\bibliography{library.bib}

\newpage

\section*{Supplementary material}

\subsection*{Equations governing reaction and diffusion of proteins in the polarity patch}

\[T42_t=(k_{2a}BG+k_3BG42+k_9RG)\cdot D42 - k_{2b}T42 - k_{4a}BG\cdot T42 + k_{4b} - k_7\cdot BGc \cdot T42 + D_m \Delta T42
\]
\[ BG42_t = k_{4a}BG\cdot T42 - k_{4b}BG42 + k_7BGc\cdot T42 + D_m\Delta BG42 \]

\[ BG_t = k_{1a}BGc - k_{1b}BG - k_{4a}BG\cdot T42+k_{4b}BG42 + D_m\Delta BG \]

\[ D42_t = k_{2b}T42 - (k_{2a}BG+k_3BG42+k_9RG)\cdot D42 + k_{6b}G42 - k_{6a}Gc\cdot D42 + D_m*\Delta D42 \]

\[ G42_t = k_{6a}Gc\cdot D42 - k_{6b}G42 + k_{5a}G42c - k_{5b}G42 + D_m\Delta G42 \]

\[ R_t = -k_{8a}\alpha\cdot R + k_{8b}RG + D_m\Delta R \]

\[ RG_t = k_{8a}\alpha\cdot R - k_{8b}RG + D_m\Delta RG

Get Access
Related
Get Access