Abstract
Soluble guanylyl cyclases are typically obligate heterodimers, composed of a single alpha and a single beta subunit. MsGC-β3, identified in the tobacco hornworm Manduca sexta, was the first example of a soluble guanylyl cyclase that exhibited enzyme activity without the need for coexpression with additional subunits. Subsequent studies have revealed that the mammalian β2 subunit also shares this property. Using a combination of gel filtration chromatography, coprecipitation and site-directed mutagenesis we show that, as predicted, MsGC-β3 forms active homodimers. We also demonstrate that MsGC-β3 is capable of forming heterodimers with the nitric oxide (NO)-sensitive guanylyl cyclase subunits MsGC-α1 and MsGC-β1. These heterodimers, however, show no enzyme activity and, like mammalian β2 subunits, act in a dominant negative manner when combined with the NO-sensitive subunits to disrupt their activation by NO. In addition, we show that the unique C-terminal domain of MsGC-β3 is not necessary for enzyme activity and might act as an auto-inhibitory domain.
Original language | English (US) |
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Pages (from-to) | 937-947 |
Number of pages | 11 |
Journal | Journal of Experimental Biology |
Volume | 206 |
Issue number | 6 |
DOIs | |
State | Published - Mar 2003 |
Keywords
- Guanylyl cyclase
- Manduca sexta
- Nitric oxide
- Protein dimerization
- Tobacco hornworm
- cGMP
ASJC Scopus subject areas
- Ecology, Evolution, Behavior and Systematics
- Physiology
- Aquatic Science
- Animal Science and Zoology
- Molecular Biology
- Insect Science