Role of scamp3 Regulating cxcr4 Trafficking

Angelika Chiang, Samantha Valaitis, and Dr. Quyen Aoh, Department of Biology, Gannon University, 109 University Square Erie, PA, 16541

The CXC-Chemokine Receptor Type 4 is a G-protein coupled receptor. The functions of CXCR4 is to regulate the growth, division, differentiation, and migration of cells. The overexpression of CXCR4 is connected to metastasis in over twenty-three types of cancer along with promoting HIV infection. Under normal conditions CXCR4 binds to its agonist CXCL12 and is endocytosed into the cell and transported to the early endosomes. At the early endosomes the CXCR4 is ubiquitinated by the ubiquitin ligase ITCH and is sorted into multivesicular bodies (MVBs) by Endosomal Sorting Complexes Required for Transport (ESCRTs). The MVBs buds off the early endosomes and are targeted for degradation in the lysosomes. The disruption of protein functions during this pathway can inhibit lysosomal degradation and lead to CXCR4 being overexpressed. In this research, we will investigate the role of SCAMP3, a Secretory Carrier Membrane Protein, which regulates CXCR4 trafficking and is known to interact with the ESCRT protein Hs and ubiquitin ligase ITCH. For our experiments Hela cells, an immortal cell line derived from cervical cancer, were used. We will first do a knockdown of SCAMP3 to silence the SCAMP3 gene and then use RNA interference to examine CXCR4 trafficking in the absence of SCAMP3, while using a well characterized immunofluorescence assay. The immunofluorescence used to determine the colocalization of CXCR4 in the lysosomes are the lysosomal markers LAMP1/2 and CXCR4 antibodies and in the early endosomes are the early endosomal markers EEA1 and CXCR4 antibodies. ImageJ colocalization program will be used to determine the colocalization between CXCR4 and organelle markers. A trafficking time course will be used to ensure that CXCR4 has arrived in the early endosomes between 30-60 minutes and in the lysosomes at 180 minutes. We anticipate that SCAMP3 could either inhibit or promote degradation of CXCR4 transportation to the lysosomes.

Additional Abstract Information

Presenters: Angelika Chiang, Samantha Valaitis

Institution: Gannon University

Type: Poster

Subject: Biology

Status: Approved

Time and Location

Session: Poster 2
Date/Time: Mon 3:00pm-4:00pm
Session Number: 2632