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. Marita Borg Distefano is the first author on ‘TBC1D5 controls the GTPase cycle of Rab7b’, published in Journal of Cell Science. Marita is a researcher in the labs of Oddmund Bakke and Cinzia Progida at the University of Oslo, Norway, investigating intracellular trafficking, Rab proteins and cell migration.

Marita Borg Distefano.

How would you explain the main findings of your paper in lay terms?

The trafficking of molecules within the cell needs to be tightly regulated in order for the cell to function properly. Rab proteins are often called master regulators of intracellular transport, since they control and coordinate almost all aspects of the different steps of intracellular traffic. However, in order for the Rab proteins to function as they should, they too need to be properly regulated both in time and in space. In our paper, we studied one member of the Rab family, namely Rab7b, and performed a screen to identify which proteins are involved in the downregulation of Rab7b activity. We found several interesting candidates, and gradually narrowed it down to one candidate: TBC1D5. We identified TBC1D5 as a GTPase-activating protein for Rab7b, meaning it shuts down the activity of Rab7b in the cell.

Were there any specific challenges associated with this project? If so, how did you overcome them?

In order to test if TBC1D5 could indeed aid in diminishing the activity of Rab7b, we needed to purify both TBC1D5 and Rab7b. The latter was not a problem to purify, but purification of TBC1D5 proved very challenging, and we struggled for quite some time without getting this protein pure enough for our assay. Luckily, by searching in the literature, we found another group that had successfully managed to purify TBC1D5, and we reached out to them, hoping they could help. The group of Da Jia was indeed very helpful and collaborative, and performed both the purification as well as the activity assay. This shows the value of having a broad network, to be able to contact other scientists that are willing to help with specific challenges.

“… [the] value of having a broad network [is] to be able to contact other scientists that are willing to help with specific challenges.”

Why did you choose Journal of Cell Science for your paper?

We have published in JCS before, and have been very happy with the fast process of revision and the constructive feedback from the reviewers. JCS is also a high-profile journal in the broad field of cellular and molecular biology, and we know that by publishing our paper here it can reach scientists all over the world.

Have you had any significant mentors who have helped you beyond supervision in the lab?

Prof. Oddmund Bakke and Dr Cinzia Progida have been my mentors during this early stage of my career. They have both helped me grow both as a person and as a scientist, and have been outstanding in their mentoring. They have pushed me to be a better scientist and showed me the way of the academic process. Dr Progida has been especially important, teaching me gradually to become more and more independent, and to trust my own thoughts and ideas, while always being supportive and full of knowledge and guidance. It has been essential for my early career development to have good mentors to help me reach my goals.

GFP-TBC1D5 and mCherryRab7b localize to the same vesicles in HeLa cells.

GFP-TBC1D5 and mCherryRab7b localize to the same vesicles in HeLa cells.

“It has been essential for my early career development to have good mentors to help me reach my goals.”

What's next for you?

I have recently finished my PhD, and am currently working as a researcher in Oslo, Norway. I have applied for funding for a mobility grant, which would allow me to continue my work as a researcher but in a different setting and a different country. I think all scientists (and non-scientists!) should aim to stay abroad for a while, to broaden their horizons, do important networking and to get to know new ways of doing things. Fingers crossed for the mobility grant!

Marita Borg Distefano's contact details: Department of Biosciences, University of Oslo, Norway.

E-mail: m.b.distefano@ibv.uio.no

Distefano
,
M. B.
,
Haugen
,
L. H.
,
Wang
,
Y.
,
Perdreau-Dahl
,
H.
,
Kjos
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I.
,
Jia
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D.
,
Morth
,
J. P.
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Neefjes
,
J.
,
Bakke
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O.
and
Progida
,
C.
(
2018
).
TBC1D5 controls the GTPase cycle of Rab7b
.
J. Cell Sci.
131
,
jcs216630
.