The Association of the Vanin-1 N131S Variant with Blood Pressure Is Mediated by Endoplasmic Reticulum-Associated Degradation and Loss of Function

Abstract

High blood pressure (BP) is the most common cardiovascular risk factor worldwide and a major contributor to heart disease and stroke. We previously discovered a BP-associated missense SNP (single nucleotide polymorphism)–rs2272996–in the gene encoding vanin-1, a glycosylphosphatidylinositol (GPI)-anchored membrane pantetheinase. In the present study, we first replicated the association of rs2272996 and BP traits with a total sample size of nearly 30,000 individuals from the Continental Origins and Genetic Epidemiology Network (COGENT) of African Americans (P = 0.01). This association was further validated using patient plasma samples; we observed that the N131S mutation is associated with significantly lower plasma vanin-1 protein levels. We observed that the N131S vanin-1 is subjected to rapid endoplasmic reticulum-associated degradation (ERAD) as the underlying mechanism for its reduction. Using HEK293 cells stably expressing vanin-1 variants, we showed that N131S vanin-1 was degraded significantly faster than wild type (WT) vanin-1. Consequently, there were only minimal quantities of variant vanin-1 present on the plasma membrane and greatly reduced pantetheinase activity. Application of MG-132, a proteasome inhibitor, resulted in accumulation of ubiquitinated variant protein. A further experiment demonstrated that atenolol and diltiazem, two current drugs for treating hypertension, reduce the vanin-1 protein level. Our study provides strong biological evidence for the association of the identified SNP with BP and suggests that vanin-1 misfolding and degradation are the underlying molecular mechanism.

Association of genetic variation with blood pressure traits among East Africans

“…Thirty single nucleotide polymorphisms (SNPs) were selected for genotyping and association analysis with BP. These SNPs were selected based on the previous association evidence with BP from GWASs or admixture mapping analysis 23,[25][26][27][28][29] (Table S1, Supporting Information).…”

Limited ER quality control for GPI-anchored proteins

“…Because of the roles of GPI-APs in prominent human diseases, including malaria ( Davidson and Gowda, 2001 ) and neurodegenerative prion diseases ( Puig et al, 2014 ; Victoria and Zurzolo, 2015 ), the intracellular quality control of selected GPI-APs has been studied extensively. Various misfolded GPI-APs accumulate in the presence of proteasome inhibitors, suggesting that ERAD is involved in their turnover ( Ma and Lindquist, 2001 ; Yedidia et al, 2001 ; Petris et al, 2014 ; Wang et al, 2014 ). However, this view was challenged by the observation that the proteasome also degrades nontranslocated species, and recent studies suggested that ER-localized misfolded GPI-APs are predominantly routed to lysosomes for degradation ( Drisaldi et al, 2003 ; Ashok and Hegde, 2008 ; Satpute-Krishnan et al, 2014 ).…”

L-type Calcium Channel Blockers Enhance Trafficking and Function of Epilepsy-associated α1(D219N) Subunits of GABAA Receptors

“…Such small molecules or biologicals are named proteostasis regulators; examples include heat shock response activators (7), unfolded protein response activation (8,9), histone deacetylase inhibitors (10), and calcium signaling regulators (11,12). In other cases, aggregation or excess of a protein is associated with diseases; therefore, it would be desirable to promote the degradation of the target protein to ameliorate such disease phenotypes (13,14). It appears that a proteostasis regulator can only work on a number of proteins, presumably because a protein utilizes a subset of proteostasis network components (15, 16), which can be specifically targeted by this proteostasis regulator.…”