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Updated: Jul 6, 2026

Comprehensive Analysis of Procoagulant Platelets Exhibiting Features of Necrosis, Apoptosis and Platelet Activation
04:37

Comprehensive Analysis of Procoagulant Platelets Exhibiting Features of Necrosis, Apoptosis and Platelet Activation

Published on: May 23, 2025

Functional characterization of twelve natural PROS1 mutations associated with anticoagulant protein S deficiency

Begoña Hurtado1, Xavier Muñoz, Maria Carme Mulero

  • 1Center de Genètica Mèdica i Molecular, IDIBELL, L'Hospitalet de Llobregat, Barcelona.

Haematologica
|March 7, 2008
PubMed
Abstract

Insights

Nonsense-mediated decay, not truncated proteins, causes protein S deficiency from PROS1 mutations. This study clarifies mechanisms for genetic variations impacting protein S levels.

Area of Science:

  • Genetics
  • Molecular Biology
  • Biochemistry

Background:

  • Protein S deficiency is linked to PROS1 mutations, but mechanisms remain unclear, especially for premature termination codons.
  • Understanding these mechanisms is crucial for diagnosing and managing inherited thrombophilia.

Purpose of the Study:

  • To investigate the functional impact of 12 PROS1 mutations on mRNA and protein expression in protein S deficiency.
  • To elucidate the molecular basis of protein S deficiency caused by various PROS1 genetic alterations.

Main Methods:

  • Analysis of PROS1 cDNA using reverse transcriptase polymerase chain reaction (RT-PCR) on platelet mRNA.
  • Site-directed mutagenesis and transient transfection of PROS1 mutants in COS-7 cells to assess protein expression and secretion.

Main Results:

  • Nonsense mutations and certain deletions/frameshifts led to the exclusion of the mutated allele, likely via nonsense-mediated mRNA decay (NMD).
  • Missense mutations and some other variants showed normal mRNA expression but resulted in reduced protein secretion (e.g., p.L15H, c.1272delA) or mild secretion (p.M640T).
  • The [c.-7C>G;44T>A] double heterozygote and p.M640T mutations allowed expression of both normal and mutated alleles.

Conclusions:

  • For premature termination codon mutations, NMD-mediated exclusion of the mutated allele is the primary cause of quantitative protein S deficiency, not truncated protein synthesis.
  • For missense mutations, defective protein synthesis, stability, or secretion are the main contributors to protein S deficiency.
  • This study clarifies the distinct molecular mechanisms underlying protein S deficiency based on PROS1 mutation type.

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