Document Type

Thesis - Open Access

Award Date

2018

Degree Name

Master of Science (MS)

Department / School

Biology and Microbiology

First Advisor

Natalie Thiex

Keywords

CSF-1R, macropinocytosis, Ptpn6

Abstract

Understanding macrophage cell biology is important due to macrophages key roles in human health and diseases including proper immune function, wound healing, atherosclerosis, and cancer. Despite their importance, relatively little is understood about macrophage activation, growth factor signaling, and cytoskeletal regulation. This thesis presents data from investigations into mechanisms of macrophage growth factor signaling and actin polymerization for ruffling and macropinocytosis. Alt-R CRISPR-Cas9 method and dextran uptake assay were used to knock out individual genes (SHP-1, Lyn, Syk, BTK, Vav1) and determine their role in macropinocytosis and CSF-1R signaling. Dextran uptake was disrupted in SHP-1 and Lyn targeted knockout cells, while it was increased in Syk, BTK, and Vav1 targeted knockout. We showed that SHP-1 and Lyn knockout express more p-Y53 actin than wildtype. We propose that SHP-1 regulates macropinocytosis through dephosphorylation of actin at tyrosine 53. Lyn colocalized on macropinosomes with CSF-1R and Lyn knockout cells faster than wildtype, suggesting their negative role in regulating growth factor signaling. However, the absence of Lyn downregulated ERK phosphorylation, suggesting that Lyn might play a role of both positive and negative regulator of signaling.

Library of Congress Subject Headings

Macrophages.
Pinocytosis.
Growth factors -- Receptors.

Description

Includes bibliographical references

Format

application/pdf

Number of Pages

98

Publisher

South Dakota State University

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Rights Statement

In Copyright