Human Polyserase-2, a Novel Enzyme with Three Tandem Serine Protease Domains in a Single Polypeptide Chain

Cal, Santiago; Quesada, Vı́ctor; Llamazares, María; Díaz‐Perales, Araceli; Garabaya, Cecilia; López-Otı́n, Carlos

doi:10.1074/jbc.m409139200

Cited by 18 publications

(24 citation statements)

References 39 publications

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“…68 Cloned in our laboratory, polyserase-1 undergoes a series of post-translational processing events to generate three distinct and independent serine protease domains termed serase-1, -2 and the catalytically inactive serase-3. 68 Further, two additional secreted poly-proteases, polyserase-2 and polyserase-3, 69,70 have been recently identified by our profiling studies of the human degradome. 71 The most studied member of the sub-family, matriptase, has been demonstrated by knockout mice studies to be required for postnatal survival, epidermal barrier function, hair follicle development and thymic homeostasis.…”

Section: The Type II Transmembrane Serine Proteasesmentioning

confidence: 99%

Matriptase-2 (TMPRSS6): a proteolytic regulator of iron homeostasis

Ramsay¹,

Hooper²,

Folgueras³

et al. 2009

Haematologica

107

104

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Maintaining the body's levels of iron within precise boundaries is essential for normal physiological function. Alterations of these levels below or above the healthy limit lead to a systemic deficiency or overload in iron. The type-two transmembrane serine protease (TTSP), matriptase-2 (also known as TMPRSS6), is attracting significant amounts of interest due to its recently described role in iron homeostasis. The finding of this regulatory role for matriptase-2 was originally derived from the observation that mice deficient in this protease present with anemia due to elevated levels of hepcidin and impaired intestinal iron absorption. Further in vitro analysis has demonstrated that matriptase-2 functions to suppress bone morphogenetic protein stimulation of hepcidin transcription through cell surface proteolytic processing of the bone morphogenetic protein co-receptor hemojuvelin. Consistently, the anemic phenotype of matriptase-2 knockout mice is mirrored in humans with matripase-2 mutations. Currently, 14 patients with iron-refractory iron deficiency anemia (IRIDA) have been reported to harbor various genetic mutations that abrogate matriptase-2 proteolytic activity. In this review, after overviewing the membrane anchored serine proteases, in particular the TTSP family, we summarize the identification and characterization of matriptase-2 and describe its functional relevance in iron metabolism.

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Section: The Type II Transmembrane Serine Proteasesmentioning

confidence: 99%

Matriptase-2 (TMPRSS6): a proteolytic regulator of iron homeostasis

Ramsay¹,

Hooper²,

Folgueras³

et al. 2009

Haematologica

107

104

View full text Add to dashboard Cite

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“…These residues should be considered in future mutagenesis studies designed to map the residues involved in the specificity of both the N-domain and C-domain of ACE. Gene duplication leading to the presence of several protease domains within a single polypeptide chain is a rare event, so far only observed in ACE, carboxypeptidase D and polyserases [23,24]. The putative functional advantages that may result from such complex protein assembly remain elusive.…”

Section: Discussionmentioning

confidence: 99%

“…In this case, independent evolution of each domain does not affect the global enzyme activity. Beside complementary enzyme activity, many other functional advantages have been proposed for these multidomain proteases, such as positive or negative cooperativity [23][24][25][26]. Clearly, a better understanding of the functional role played by each domain in these intriguing proteases will require additional studies.…”

Section: Discussionmentioning

confidence: 99%

Combined use of selective inhibitors and fluorogenic substrates to study the specificity of somatic wild‐type angiotensin‐converting enzyme

et al. 2006

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Angiotensin-converting enzyme (ACE) in vertebrates is a zinc metallopeptidase involved in the release of angiotensin II and the inactivation of bradykinin, two peptide hormones that play a key role in blood pressure regulation and renal and cardiovascular function [1][2][3][4]. ACE inhibitors have been on the market for more than 20 years, with successful applications for conditions ranging from mild hypertension to postmyocardial infarction [5,6]. Somatic ACE is a very unusual enzyme which contains two active sites on the same polypeptide chain [7]. Since this discovery, there has been much speculation about the functional significance of the presence of two active sites in the same enzyme [8][9][10][11][12][13]. At the biochemical level, the presence of two active sites in the same enzyme has hampered the full characterization of substrate and inhibitor selectivity of somatic ACE. To circumvent these limitations, mutants of human ACE containing a single functional active site [14,15] or isolated ACE domains have been utilized to perform these studies [10,11]. Alternative approaches to study directly the properties of both domains in somatic form of ACE are still lacking. The development of the first highly N-domain-specific inhibitor, RXP407 [16], and the recent identification of a C-domain-specific inhibitor, RXPA380 [13], of human ACE may provide such an alternative strategy for studying inhibitor and substrate selectivity of any form of somatic ACE (Scheme 1). To demonstrate its interest, this approach was used to study the selectivity of somatic ACE purified from Somatic angiotensin-converting enzyme (ACE) contains two homologous domains, each bearing a functional active site. Studies on the selectivity of these ACE domains towards either substrates or inhibitors have mostly relied on the use of mutants or isolated domains of ACE. To determine directly the selectivity properties of each ACE domain, working with wildtype enzyme, we developed an approach based on the combined use of N-domain-selective and C-domain-selective ACE inhibitors and fluorogenic substrates. With this approach, marked differences in substrate selectivity were revealed between rat, mouse and human somatic ACE. In particular, the fluorogenic substrate Mca-Ala-Ser-Asp-Lys-DpaOH was shown to be a strict N-domain-selective substrate of mouse ACE, whereas with rat ACE it displayed marked C-domain selectivity. Similar differences in selectivity between these ACE species were also observed with a new fluorogenic substrate of ACE, Mca-Arg-Pro-Pro-Gly-Phe-Ser-Pro-DpaOH. In support of these results, changes in amino-acid composition in the binding site of these three ACE species were pinpointed. Together these data demonstrate that the substrate selectivity of the N-domain and C-domain depends on the ACE species. These results raise concerns about the interpretation of functional studies performed in animals using N-domain and C-domain substrate selectivity data derived only from human ACE.Abbreviations ACE, angiotensin-converting enzyme; DpaOH...

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“…Interestingly, analysis of post-translational processing mechanisms of polyserase-1 revealed that it is synthesized as a membrane-bound protein which undergoes a series of proteolytic processing events to generate three independent serine protease domains [ 9 ]. Further studies of the human degradome have revealed the occurrence of another gene coding for a protein with three tandem serine protease domains in a single polypeptide chain [ 3 ]. This protein – called polyserase-2 – is an extracellular glycosylated enzyme, whose three serine protease domains are not proteolytically cleaved and remain as an integral part of the same polypeptide chain.…”

Section: Introductionmentioning

confidence: 99%

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et al. 2006

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BackgroundWe have previously described the identification and characterization of polyserase-1 and polyserase-2, two human serine proteases containing three different catalytic domains within the same polypeptide chain. Polyserase-1 shows a complex organization and it is synthesized as a membrane-bound protein which can generate three independent serine protease domains as a consequence of post-translational processing events. The two first domains are enzymatically active. By contrast, polyserase-2 is an extracellular glycosylated protein whose three protease domains remain embedded in the same chain, and only the first domain possesses catalytic activity.ResultsFollowing our interest in the study of the human degradome, we have cloned a human liver cDNA encoding polyserase-3, a new protease with tandem serine protease domains in the same polypeptide chain. Comparative analysis of polyserase-3 with the two human polyserases described to date, revealed that this novel polyprotein is more closely related to polyserase-2 than to polyserase-1. Thus, polyserase-3 is a secreted protein such as polyserase-2, but lacks additional domains like the type II transmembrane motif and the low-density lipoprotein receptor module present in the membrane-anchored polyserase-1. Moreover, analysis of post-translational mechanisms operating in polyserase-3 maturation showed that its two protease domains remain as integral parts of the same polypeptide chain. This situation is similar to that observed in polyserase-2, but distinct from polyserase-1 whose protease domains are proteolytically released from the original chain to generate independent units. Immunolocalization studies indicated that polyserase-3 is secreted as a non-glycosylated protein, thus being also distinct from polyserase-2, which is a heavily glycosylated protein. Enzymatic assays indicated that recombinant polyserase-3 degrades the α-chain of fibrinogen as well as pro-urokinase-type plasminogen activator (pro-uPA). Northern blot analysis showed that polyserase-3 exhibits a unique expression pattern among human polyserases, being predominantly detected in testis, liver, heart and ovary, as well as in several tumor cell lines.ConclusionThese findings contribute to define the growing group of human polyserine proteases composed at present by three different proteins. All of them share a complex structural design with several catalytic units in a single polypeptide but also show specific features in terms of enzymatic properties, expression patterns and post-translational maturation mechanisms.

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Human Polyserase-2, a Novel Enzyme with Three Tandem Serine Protease Domains in a Single Polypeptide Chain

Cited by 18 publications

References 39 publications

Matriptase-2 (TMPRSS6): a proteolytic regulator of iron homeostasis

Matriptase-2 (TMPRSS6): a proteolytic regulator of iron homeostasis

Combined use of selective inhibitors and fluorogenic substrates to study the specificity of somatic wild‐type angiotensin‐converting enzyme

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