Neurocalcin δ modulation of ROS-GC1, a new model of Ca2+ signaling

Venkateswar Venkataraman, Teresa Duda, Sarangan Ravichandran, Rameshwar K. Sharma

Research output: Contribution to journalArticlepeer-review

39 Scopus citations

Abstract

ROS-GC1 membrane guanylate cyclase is a Ca2+ bimodal signal transduction switch. It is turned "off" by a rise in free Ca 2+ from nanomolar to the semicromolar range in the photoreceptor outer segments and the olfactory bulb neurons; by a similar rise in the bipolar and ganglion retinal neurons it is turned "on". These opposite operational modes of the switch are specified by its Ca2+ sensing devices, respectively termed GCAPs and CD-GCAPs. Neurocalcin δ is a CD-GCAP. In the present study, the neurocalcin δ-modulated site, V 837-L858, in ROS-GC1 has been mapped. The location and properties of this site are unique. It resides within the core domain of the catalytic module and does not require the α-helical dimerization domain structural element (amino acids 767-811) for activating the catalytic module. Contrary to the current beliefs, the catalytic module is intrinsically active; it is directly regulated by the neurocalcin δ-modulated Ca2+ signal and is dimeric in nature. A fold recognition based model of the catalytic domain of ROS-GC1 was built, and neurocalcin r5 docking simulations were carried out to define the three-dimensional features of the interacting domains of the two molecules. These findings define a new transduction model for the Ca2+ signaling of ROS-GC1.

Original languageEnglish (US)
Pages (from-to)6590-6601
Number of pages12
JournalBiochemistry
Volume47
Issue number25
DOIs
StatePublished - Jun 24 2008
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry

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