The long-term objective of this project is to understand the signaling mechanisms and physiological functions of the newly discovered Rac-cGMP pathway. Many membrane-signaling receptors can increase the cellular levels of the ubiquitous second messenger cyclic GMP (cGMP). However, the molecular mechanism by which these membrane-signaling receptors increased cGMP was not known. We recently uncovered a new Rac-cGMP signaling pathway. The small G protein Rac uses its effector PAK (p21-activated kinase) to allosterically activate transmembrane guanylyl cyclases (GCs). These findings reveal a general mechanism for diverse signaling receptors to modulate physiological responses through cGMP. Although the kinase activity of PAK is required, PAK does not directly phosphorylate GCs. Instead, autophosphorylation of PAK is needed to maintain its activated configuration. The active form of PAK then allosterically activates transmembrane GCs. The main focus of this application is on the biochemical mechanism by which Rac, through its effector PAK, regulates the activity of transmembrane guanylyl cyclases. We will investigate the allosteric activation of transmembrane guanylyl cyclases by PAK in the Specific Aim 1. In the Specific Aim 2, we will explore the signaling molecules downstream of cGMP. We will investigate the physiological function of the Rac-cGMP pathway in the Specific Aim 3.

Public Health Relevance

This research is directly related to human health. Both Rac GTPase and the second messenger cGMP are critical regulators of many physiological functions. Cell migration and vascular permeability are essential for vascular development and are involved in cardiovascular diseases. Investigations of the signaling mechanisms and physiological functions of the Rac-cGMP pathway will significantly advance our understanding of cardiovascular function and diseases.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM084191-03
Application #
8021806
Study Section
Molecular and Integrative Signal Transduction Study Section (MIST)
Program Officer
Dunsmore, Sarah
Project Start
2009-01-01
Project End
2012-12-31
Budget Start
2011-01-01
Budget End
2011-12-31
Support Year
3
Fiscal Year
2011
Total Cost
$339,557
Indirect Cost
Name
Weill Medical College of Cornell University
Department
Physiology
Type
Schools of Medicine
DUNS #
060217502
City
New York
State
NY
Country
United States
Zip Code
10065
Smith, Heidi K; Luo, Linjiao; O'Halloran, Damien et al. (2013) Defining specificity determinants of cGMP mediated gustatory sensory transduction in Caenorhabditis elegans. Genetics 194:885-901
Snyder, Marylynn; Huang, Xin-Yun; Zhang, J Jillian (2011) Stat3 is essential for neuronal differentiation through direct transcriptional regulation of the Sox6 gene. FEBS Lett 585:148-52
Guo, Dagang; Zhang, J Jillian; Huang, Xin-Yun (2010) A new Rac/PAK/GC/cGMP signaling pathway. Mol Cell Biochem 334:99-103
Guo, Dagang; Zhang, J Jillian; Huang, Xin-Yun (2009) Stimulation of guanylyl cyclase-D by bicarbonate. Biochemistry 48:4417-22