Molecular cloning and characterization of a tobacco MAP kinase kinase that interacts with SIPK

A tobacco MAP kinase termed SIPK (Salicylic acid-Induced Protein Kinase) is activated in response to a variety of stress signals, including pathogen attack and wounding (S. Zhang and D.F. Klessig, Proc. Natl. Acad. Sci. USA 95:7225-7230, 1998; S. Zhang and D.F. Klessig, Proc. Natl. Acad. Sci. USA 95:7433-7438, 1998). Using the yeast two-hybrid system, we have identified a gene encoding a protein that interacts with SIPK but not the wounding induced protein kinase (WIPK), which is another tobacco MAP kinase. Sequence analysis indicated that this SIPK-interacting protein is a member of the MAP kinase kinase family; thus, it was named SIPK kinase (SIPKK). Co-immunoprecipitation experiments demonstrated that SIPKK and SIPK interact in vitro. Consistent with its putative function as a kinase, SIPKK phosphorylated myelin basic protein in vitro. Interestingly, SIPKK was induced at the mRNA level after Tobacco mosaic virus (TMV) infection or wounding, albeit with kinetics that are too slow to account for the activation of SIPK following these stimuli.     

Chromosomal locations of members of a family of novel endogenous human retroviral genomes.

Human cellular DNA contains two distinguishable families of retroviral related sequences. One family shares extensive nucleotide sequence homology with infectious mammalian type C retroviral genomes (T. I. Bonner, C. O'Connell, and M. Cohen, Proc. Natl. Acad. Sci. USA 79:4709-4713, 1982; M. A. Martin, T. Bryan, S. Rasheed, and A. S. Khan, Proc. Natl. Acad. Sci. USA 78:4892-4896, 1981). The other family contains major regions of homology with the pol genes of infectious type A and B and avian type C and D retroviral genomes (R. Callahan, W. Drohan, S. Tronick, and J. Schlom, Proc. Natl. Acad. Sci. USA 79:5503-5507, 1982; I. M. Chiu, R. Callahan, S. R. Tronick, J. Schlom, and S. A. Aaronson, Science 223:364-370, 1984). Analysis of the human recombinant clone HLM-2 has shown that the pol gene in the latter family is located within an endogenous proviral genome (R. Callahan, I. M. Chiu, J. F. H. Wong, S. R. Tronick, B. A. Roe, S. A. Aaronson, and J. Schlom, Science 228:1208-1211, 1985). We show that the proviral genome in HLM-2 and the related recombinant clone HLM-25 are located, respectively, on human chromosomes 1 and 5. Other related proviral genomes are located on chromosomes 7, 8, 11, 14, and 17.     

A general requirement for FcγRIIB co-engagement of agonistic anti-TNFR antibodies

Comment on: Li F, et al. Proc Natl Acad Sci USA 2012; 109:10966-71.     

Could TCTP contribute to Armin Braun's paradigm of tumor reversion in plants?

Comment on: Brioudes F, et al. Proc Natl Acad Sci USA 2010; 107:16384-9.     

Dynamics of the recovery from sRNA-mediated gene silencing

Comment on: Mitarai N, Benjamin JA, Krishna S, Semsey S, Csiszovszki Z, Massé E, et al. Dynamic features of gene expression control by small regulatory RNAs. Proc Natl Acad Sci USA 2009; 106:10655-9.     

Glycogen synthase kinase (GSK)-3 and mammalian target of rapamycin complex 1 (mTORC1) cooperate to regulate protein S6 kinase 1 (S6K1)

Comment on: Shin S, et al. Proc Natl Acad Sci USA 2011; 108:1204–13     

A microRNA regulating adult hematopoietic stem cells

Comment on: Guo S, et al. Proc Natl Acad Sci USA 2010; 107:14229-34.     

Connection between induction of DNA lesions and DNA recombination/repair during Ig class switch recombination

Comment on: Kracker S, et al. Proc Natl Acad Sci USA 2010; 107:22225-30.