In flies, the gene lightoid encodes a Rab GTPase that plays an important role in
ID: 167429 • Letter: I
Question
In flies, the gene lightoid encodes a Rab GTPase that plays an important role in vesicle trafficking of eye pigments. Mutants that produce nonfunctional versions of the lightoid protein have eyes with light colored patches in their eyes. Suppose that the lightoid protein functions specifically in vesicles in the cis Golgi and medial cisternae. How would each of the following processes be affected (not at all, somewhat impaired, or completely impaired) in the lightoid mutants. Give a brief answer for each.
a. Secretion of pigment proteins from eye cells through exocytosis
b. Translocation of a pigment protein into the ER
c. Anterograde transport of pigment proteins from the ER to the Golgi
Explanation / Answer
A few facts before answering the questions:
> Pigments are synthesized in ER on ribosomes and transferred to Golgi and secreted to outside.
> The gene lightoid encodes a Rab GTPase which is involved in vesicle trafficking, will effect majorily transfer of vesicles from Golgi to other parts of the cell or outside of the cell
In light of the above facts, the answers will be:
a. The secretion of pigment proteins from eye cells through exocytosis shall be completely affected
b. Translocation of a pigment protein into the ER may be somewhat impared in cases if it is there
c. Anterograde transport of pigment proteins from the ER to the Golgi will not be there at all since the protein lightoid does not play a role in this kind of transport from ER to Golgi.
Best,