PMID- 10336608
OWN - NLM
STAT- MEDLINE
DCOM- 19990624
LR  - 20190620
IS  - 0014-2956 (Print)
IS  - 0014-2956 (Linking)
VI  - 262
IP  - 2
DP  - 1999 Jun
TI  - A novel isoform of the low molecular weight phosphotyrosine phosphatase, LMPTP-C, 
      arising from alternative mRNA splicing.
PG  - 277-82
AB  - The low molecular weight protein tyrosine phosphatase (LMPTP) is an 18-kDa enzyme 
      that it distantly related to other protein tyrosine phosphatases. The single gene 
      for LMPTP is known to undergo an alternative splicing event in which exon 3 or 
      exon 4 is excised, resulting in two isoforms termed A and B; the latter is more 
      mobile in SDS/PAGE. In this paper we report the existence of a third isoform, 
      which we call C, in which both exons 3 and 4 are lacking. We find the resulting 
      mRNA to be ubiquitously expressed at levels that exceed those of the mRNAs for 
      isoforms A and B. This mRNA was reverse-transcribed, cloned and sequenced, 
      confirming the direct splicing of exon 2 to exon 5. In-vitro transcription and 
      translation of the cDNA for the novel isoform resulted in the expected 16 kDa 
      protein. This protein was also detected in Jurkat T cells using an antipeptide 
      antiserum. LMPTP-C immunoprecipitated from transfected cells, as well as 
      bacterially produced recombinant LMPTP-C, lacked phosphatase activity. Unlike 
      LMPTP-B, LMPTP-C was not phosphorylated on tyrosine when coexpressed with Lck 
      despite the presence of the two acceptor tyrosines. Finally, whereas c-fos 
      induction by platelet-derived growth factor was inhibited by LMPTP-B, LMPTP-C 
      augmented it. These results suggest that the lack of the 38-amino acid fragment 
      encoded by exon 3 or 4 results in a protein product with a different 
      three-dimensional folding, that lacks a functional catalytic pocket and that may 
      function as a natural antagonist of isoforms A and B.
FAU - Tailor, P
AU  - Tailor P
AD  - Division of Cell Biology, La Jolla Institute for Allergy and Immunology, San 
      Diego, CA, USA. tmustelin@skcc.org
FAU - Gilman, J
AU  - Gilman J
FAU - Williams, S
AU  - Williams S
FAU - Mustelin, T
AU  - Mustelin T
LA  - eng
GR  - AI35603/AI/NIAID NIH HHS/United States
GR  - AI41481/AI/NIAID NIH HHS/United States
GR  - GM48960/GM/NIGMS NIH HHS/United States
GR  - etc.
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - England
TA  - Eur J Biochem
JT  - European journal of biochemistry
JID - 0107600
RN  - 0 (DNA Primers)
RN  - 0 (Isoenzymes)
RN  - 0 (RNA, Messenger)
RN  - EC 3.1.3.48 (Protein Tyrosine Phosphatases)
SB  - IM
MH  - *Alternative Splicing
MH  - Animals
MH  - Base Sequence
MH  - Cell Line
MH  - Cloning, Molecular
MH  - DNA Primers
MH  - Humans
MH  - Isoenzymes/*genetics
MH  - Molecular Weight
MH  - Protein Tyrosine Phosphatases/*genetics
MH  - RNA, Messenger/*genetics
EDAT- 1999/05/21 00:00
MHDA- 1999/05/21 00:01
CRDT- 1999/05/21 00:00
PHST- 1999/05/21 00:00 [pubmed]
PHST- 1999/05/21 00:01 [medline]
PHST- 1999/05/21 00:00 [entrez]
AID - 10.1046/j.1432-1327.1999.00353.x [doi]
PST - ppublish
SO  - Eur J Biochem. 1999 Jun;262(2):277-82. doi: 10.1046/j.1432-1327.1999.00353.x.