Vesicular Trafficking Defects, Developmental Abnormalities, and Alterations in the Cellular Death Process Occur in Cell Lines that Over-Express Dictyostelium GTPase, Rab2, and Rab2 Mutants

Katherine Maringer; Entsar Saheb; John Bush

doi:10.3390/biology3030514

Vesicular Trafficking Defects, Developmental Abnormalities, and Alterations in the Cellular Death Process Occur in Cell Lines that Over-Express Dictyostelium GTPase, Rab2, and Rab2 Mutants

Biology (Basel). 2014 Aug 25;3(3):514-35. doi: 10.3390/biology3030514.

Authors

Katherine Maringer¹, Entsar Saheb², John Bush³

Affiliations

¹ Department of Biology, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, AR 72205, USA. kvmaringer@hotmail.com.
² Department of Biology, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, AR 72205, USA. ejsaheb@ualr.edu.
³ Department of Biology, University of Arkansas at Little Rock, 2801 S. University Ave., Little Rock, AR 72205, USA. Jmbush@ualr.edu.

Abstract

Small molecular weight GTPase Rab2 has been shown to be a resident of pre-Golgi intermediates and required for protein transport from the ER to the Golgi complex, however, the function of Rab2 in Dictyostelium has yet to be fully characterized. Using cell lines that over-express DdRab2, as well as cell lines over-expressing constitutively active (CA), and dominant negative (DN) forms of the GTPase, we report a functional role in vesicular transport specifically phagocytosis, and endocytosis. Furthermore, Rab2 like other GTPases cycles between an active GTP-bound and an inactive GDP-bound state. We found that this GTP/GDP cycle for DdRab2 is crucial for normal Dictyostelium development and cell-cell adhesion. Similar to Rab5 and Rab7 in C. elegans, we found that DdRab2 plays a role in programmed cell death, possibly in the phagocytic removal of apoptotic corpses.