Investigation of The Role of KrsB in Rap1-Mediated Adhesion of Dictyostelium discoideum

Material Information

Title:
Investigation of The Role of KrsB in Rap1-Mediated Adhesion of Dictyostelium discoideum
Creator:
Kelsey Roberts
Yulia Artemenko

Notes

Abstract:
Dictyostelium discoideum is a model organism commonly used to study cell migration because of its similarities to other amoeboid cells, such as neutrophils and metastatic cancer cells. Rap1 is a small GTPase that increases cell adhesion, which is necessary for proper migration, by regulating myosin II and talin. Kinase responsive to stress B (KrsB) is a kinase that negatively regulates cell adhesion, although the molecular mechanism of its action is unknown. Preliminary evidence from our laboratory suggested that while Rap1 does not require KrsB for its effects on adhesion, KrsB might be a negative regulator of Rap1. The goal of this study was to examine the behavior of cells expressing Rap1 in the presence or absence of KrsB to determine if KrsB indeed negatively regulates Rap1. It was predicted that cells expressing Rap1 in the absence of KrsB would show increased spreading and, consequently, decreased migration, while cells expressing both Rap1 and KrsB would show decreased spreading and increased migration. Two cell lines were generated from KrsB-null cells, one with RFP-tagged Rap1 G12V (constitutively active Rap1) and one with RFP-tagged pDM318 (empty vector). In addition, both cell lines were also transformed with GFP-tagged KrsB under an inducible promoter. Each cell line was either induced with doxycycline to express KrsB-GFP, or not induced (KrsB-null). Random migration and spreading were imaged using brightfield illumination, and RFP-Rap1 and KrsB-GFP expression was confirmed using epifluorescence. Under the conditions tested, spreading appeared to be equal between all four cell lines, whereas migration increased in the presence of KrsB both in Rap1 G12V and vector expressing cells. These findings were unexpected given the known effect of Rap1 G12V on cell spreading. Future studies will examine behavior of the cell lines under conditions that are more optimal for cell spreading and will also select cells that have high Rap1 G12V expression for analysis.
Acquisition:
Collected for SUNY Oswego Institutional Repository by the online self-submittal tool. Submitted by Kelsey Roberts.

Record Information

Source Institution:
SUNY Oswego Institutional Repository
Holding Location:
SUNY Oswego Institution
Rights Management:
All applicable rights reserved by the source institution and holding location.
Embargo Date:
9/13/2020