Export is the default pathway for soluble unfolded polypeptides that accumulate during expression in Escherichia coli.

Several E. coli endogenous, cytoplasmic proteins that are known clients of the chaperonin GroEL were overexpressed to examine the fate of accumulated unfolded polypeptides. Substantial fractions of about half of the proteins formed insoluble aggregates, consistent with the hypothesis that these proteins were produced at rates or in amounts that exceeded the protein-folding capacity of GroEL.

Basis for the isoform-specific interaction of myosin phosphatase subunits protein phosphatase 1c beta and myosin phosphatase targeting subunit 1.

Myosin II association with actin, which triggers contraction, is regulated by orchestrated waves of phosphorylation/dephosphorylation of the myosin regulatory light chain. Blocking myosin regulatory light chain phosphorylation with small molecule inhibitors alters the shape, adhesion, and migration of many types of smooth muscle and cancer cells. Dephosphorylation is mediated by myosin phosphatase (MP), a complex that consists of a catalytic subunit (protein phosphatase 1c, PP1c), a large subunit (myosin phosphatase targeting subunit, MYPT), and a small subunit of unknown function.

Identification of alternative transcripts using rapid amplification of cDNA ends (RACE).

Many organisms, including humans, have many more proteins than are actually coded for by their genes. This discrepancy is partially explained by the existence of alternative transcripts produced by the same gene. Multiple isoforms of the same gene sometimes perform completely different functions, and as such, knowing the sequence of one of the transcripts is not enough.

Amplification of 5' end cDNA with 'new RACE'.

'New RACE' (rapid amplification of cDNA ends) PCR is a method for obtaining full-length cDNA for mRNA for which only part of the sequence is known. Starting with cellular mRNA, PCR is used to amplify regions between the known parts of the sequence and nonspecific tags at the ends of the cDNA. In 'new RACE', an anchor is ligated to the 5' end of the mRNA before reverse transcription, resulting in the selective production of full-length 5' cDNA ends.

3' end cDNA amplification using classic RACE.

Having knowledge of the entire 3' sequence of a cDNA is often important because the non-coding terminal region can contain signals that regulate the stability or subcellular localization of the mRNA. Also, some messages use alternative genomic sites for cleavage and polyadenylation that can alter the above properties, or change the encoded protein. Full-length cDNAs can be obtained from complex mixtures of cellular mRNA using rapid amplification of cDNA ends (RACE) PCR as long as part of the mRNA sequence is known; adding non-specific tags to the ends of the cDNA allows the regions between the known parts of the sequence and the ends to be amplified.

5' end cDNA amplification using classic RACE.

The 5' ends of transcripts provide important information about transcription initiation sites and the approximate locations of local cis-acting enhancer elements; it is therefore important to establish the 5' ends with some precision. RACE (rapid amplification of cDNA ends) PCR is useful for quickly obtaining full length cDNAs for mRNAs for which only part of the sequence is known and to identify alternative 5' or 3' ends of fully sequenced genes. The method consists of using PCR to amplify, from complex mixtures of cellular mRNA, the regions between the known parts of the sequence and non-specific tags appended to the ends of the cDNA.

Differential modification of Ras proteins by ubiquitination.

Ras proteins are essential components of signal transduction pathways that control cell proliferation, differentiation, and survival. It is well recognized that the functional versatility of Ras proteins is accomplished through their differential compartmentalization, but the mechanisms that control their spatial segregation are not fully understood. Here we show that HRas is subject to ubiquitin conjugation, whereas KRas is refractory to this modification.