Transglutaminase aggregates huntingtin into nonamyloidogenic polymers, and its enzymatic activity increases in Huntington's disease brain nuclei

Marcela V. Karpuj, Hideki Garren, Hilda Slunt, Donald L. Price, James Gusella, Mark W. Becher, Lawrence Steinman

Research output: Contribution to journalArticlepeer-review

205 Scopus citations

Abstract

The protein huntingtin (htt), aggregated in neuronal nuclear inclusions, is pathognomonic of Huntington's disease (HD). Constructs, translated in vitro from the N terminus of htt, containing either polyQ23 from a normal individual, or polyQ41 or polyQ67 from an HD patient, were all soluble. Transglutaminase (TGase) crosslinked these proteins, and the aggregations did not have the staining properties of amyloid. More TGase-catalyzed aggregates formed when the polyglutamine domain of htt exceeded the pathologic threshold of polyQ36. Furthermore, shorter htt constructs, containing 135 aa or fewer, formed more aggregates than did larger htt constructs. TGase activity in the HD brain was increased compared with the control, with notable increases in cell nuclei. The increased TGase activity was brain specific. In lymphoblastoid cells from HD patients, TGase activity was decreased. TGase- mediated crosslinking of htt may be involved in the formation of the nonamyloidogenic nuclear inclusions found in the HD brain. The staining properties of nuclear inclusions in the HD brain revealed that they were not amyloid.

Original languageEnglish (US)
Pages (from-to)7388-7393
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume96
Issue number13
DOIs
StatePublished - Jun 22 1999
Externally publishedYes

ASJC Scopus subject areas

  • General

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