The proposed work seeks to define the structural requirements of a Ca2+-dependent GCAP that are essential for activation of the photoreceptor-specific GC during the recovery process that follows visual excitation. Mutations will be introduced into GCAP and the mutant protein expressed using a baculovirus expression system. Targets for mutagenesis include: (1) a point mutation at the site of myristoylation; (2) point mutations for each of the three Ca2+ binding sites; (3) N-terminal deletion mutants which retain the myristoylation site but lack regions thought to be involved in GC activation, and; (4) C-terminal deletions. The mutants will be analyzed for their ability to activate GC in a Ca2+-dependent manner. Relevant mutants will be further characterized to determine changes in protein conformation, ability to bind Ca2+, ability to interact with membranes, kinetics of activation of GC, and their physiological effect on the recovery of the photoresponse in intact photoreceptors.

Agency
National Institute of Health (NIH)
Institute
National Eye Institute (NEI)
Type
First Independent Research Support & Transition (FIRST) Awards (R29)
Project #
5R29EY011268-04
Application #
2888491
Study Section
Special Emphasis Panel (ZRG1-VISC (01))
Project Start
1996-08-01
Project End
2001-07-31
Budget Start
1999-08-01
Budget End
2000-07-31
Support Year
4
Fiscal Year
1999
Total Cost
Indirect Cost
Name
Baylor College of Medicine
Department
Ophthalmology
Type
Schools of Medicine
DUNS #
074615394
City
Houston
State
TX
Country
United States
Zip Code
77030
Howes, K; Bronson, J D; Dang, Y L et al. (1998) Gene array and expression of mouse retina guanylate cyclase activating proteins 1 and 2. Invest Ophthalmol Vis Sci 39:867-75