ABSTRACT
First Person is a series of interviews with the first authors of a selection of papers published in Journal of Cell Science, helping early-career researchers promote themselves alongside their papers. Khamal Kwesi Ampah is the first author on ‘S-acylation regulates the trafficking and stability of the unconventional Q-SNARE STX19’, published in Journal of Cell Science. Khamal did his PhD with Andrew Peden at the University of Sheffield, UK, and is currently a postdoc in the lab of Professor Polly Roy at London School of Hygiene and Tropical Medicine, UK, investigating the therapeutic potential of oncolytic virus in the treatment of cancer.
Khamal Kwesi Ampah
How would you explain the main findings of your paper in lay terms?
All eukaryotic cells contain numerus compartments (organelles), which are surrounded by membranes made from lipids and proteins. A major area of research in the field of cell biology is trying to understand how proteins and lipids are transported between these organelles. In this study, we set out to understand how a protein named STX19 is targeted to membranes. We discovered that STX19 is targeted to membranes via a lipid modification termed S-acylation and that this modification also helps to protect the protein from degradation. One of the most surprising and unexpected findings of our study was that this S-acylation also controls the route by which STX19 is targeted to membranes. This observation suggests that S-acylation may have a more important role in telling proteins where to go within the cell than previously anticipated.
Were there any specific challenges associated with this project? If so, how did you overcome them?
From our cell biology-based experiments it became apparent that the function of STX19 is regulated by S-acylation. However, my group did not have experience in this field, so we realised that if we were to address this question, we would need to establish collaborations with other groups. The scientific input and technical expertise provide by Dr Mark Collins, Dr Luke Chamberlain and Dr Jennifer Greaves really helped us to address our research question and significantly improved the quality of our manuscript. Our rabbit polyclonal antibody to STX19 works only for immunostaining, thus most of our biochemical experiments had to be done using recombinant STX19.
When doing the research, did you have a particular result or ‘eureka’ moment that has stuck with you?
The eureka moment came after when we fused the cysteine-rich domain of STX19 onto a GFP and then transfected HeLaM cells with it. The otherwise diffuse cytosolic GFP protein became targeted to membranes just like the full-length STX19, showing that the cysteine-rich domain was necessary and sufficient for STX19 localisation. More exciting findings followed when our mass spectrometry analysis identified specific free cysteine sites in STX19 that could be S-acylated. S-acylation is catalysed by enzymes called S-acyltransferases, and our study culminated in the characterisation of the putative S-acyltransferases that undertook modification of STX19 out of the 24 known enzymes.
Why did you choose Journal of Cell Science for your paper?
My supervisor has always been a big fan of the journal. When he was an undergraduate working in the library, he was always drawn to the journal because of its striking cover art.
Have you had any significant mentors who have helped you beyond supervision in the lab?
As the first PhD student to join Dr Peden's lab at the University of Sheffield, I enjoyed tremendous support in learning new techniques and designing experiments. Andrew was readily available to help with troubleshooting when experiments go wrong. His excellent networking ability provided me with opportunities to work and collaborate on several projects. In addition, I benefited from the biannual meetings with two distinguished advisors, Professor Kathryn Ayscough and Dr Kai Erdmann, whose constructive suggestions helped to steer my projects in the right direction.
“I get my role models from every peer-reviewed paper I read and from every scientific lecture I listen or watch.”
Super-resolution image of a fixed HeLa cell. The cell is stained with antibodies against endogenous MICAL-L1 (red) and STX19 (green), illustrating that a pool of STX19 and MICAL-L1 are found on tubular recycling endosomes. The nucleus is counterstained with DAPI. Images were acquired using a 3D-SIM OMX based in The Wolfson Light Microscopy Facility, University of Sheffield with technical support by Dr Darren Robinson. A maximum intensity image was generated for each channel and merged using ImageJ.
Super-resolution image of a fixed HeLa cell. The cell is stained with antibodies against endogenous MICAL-L1 (red) and STX19 (green), illustrating that a pool of STX19 and MICAL-L1 are found on tubular recycling endosomes. The nucleus is counterstained with DAPI. Images were acquired using a 3D-SIM OMX based in The Wolfson Light Microscopy Facility, University of Sheffield with technical support by Dr Darren Robinson. A maximum intensity image was generated for each channel and merged using ImageJ.
Who are your role models in science? Why?
As Confucius said, “Walking among three people, I find my teacher among them. I choose that which is good in them and follow it, and that which is bad and change it”. There are a lot of researchers out there whom I do recognise as my role models. I get my role models from every peer-reviewed paper I read and from every scientific lecture I listen or watch. I am guided by their enthusiasm and passion that drives them to succeed and excel.
What's next for you?
I am currently pursuing a postdoctoral research fellow programme in the Department of Infectious and Tropical Disease at London School of Hygiene & Tropical Medicine Department. My projects in Polly Roy's lab focuses on the role of the capsid protein VP5 and the non-structural protein NS2 in Bluetongue virus replication. This work involves the use of reverse genetics and baculovirus recombinant protein expression, coupled with protein structural analysis and microscopy to understand the molecular mechanisms underlying the role of VP5 and NS2 in Bluetongue virus replication.
Tell us something interesting about yourself that wouldn't be on your CV
Apart from academia, I am very interested in volunteering. I have been involved in tree planting, street cleaning and supplying quality water.
Khamal Kwesi Ampah's contact details: London School of Hygiene and Tropical Medicine, Department of Infectious and Tropical Disease, Keppel Street, WC1E 7HT, London, UK.
E-mail: [email protected]
