Primary structure of the site on bovine hormone‐sensitive lipase phosphorylated by cyclic AMP‐dependent protein kinase

Abstract

The primary structure of a region on hormone‐sensitive lipase was determined to be: Lys‐Thr‐Glu‐Pro‐Met‐Arg‐Arg‐Ser‐Val‐Ser‐Glu‐Ala‐Ala‐Leu‐Thr‐Gln‐Pro‐Glu‐Gly‐Pro‐Leu‐Gly‐Thr‐Asp‐Ser‐Leu‐Lys. Ser‐8 was the only residue in the intact protein phosphorylated by cyclic AMP‐dependent protein kinase. However, Ser‐10 also appeared to be present in a phosphorylated form, suggesting that it is a target for a distinct protein kinase in vivo.

Phosphorylation and activation of hormone‐sensitive lipase in isolated macrophages

“…A key feature of HSL is its ability to be activated by phosphorylation by cyclic AMPdependent protein kinase [5][6][7]. Consistent ~ith this, Goldberg cell-free extracts of P388D~ macrophages by cyclic AMP-dependent protein kinase, and in intact cells by elevation of intracellular cyclic AMP levels [81.…”

Phosphorylation of bovine hormone‐sensitive lipase by the AMP‐activated protein kinase

“…We have recently shown that tryptic phosphopeptides containing the site on bovine HSL which is phosphorylated by cyclic-AMP-dependent protein kinase (SVSEAALTQPEG-PLGTDSLK) also contain a second phosphorylated residue (SVSEAALTQPEGPLGTDSLK) (site 2), which is not modified by cyclic-AMP-dependent protein kinase, but which is already partially phosphorylated in the enzyme, as prepared, indicating that this residue represents an in vivo site of phosphorylation [5]. Work with rat adipocytes has also demonstrated the presence of a second site of phosphorylation on Carrespondence to…”

“…This leads to phosphorylation of HSL which activates the enzyme and therefore stimulates lipolysis [2]. The major antilipolytic hormone is insulin which acts, at least in part, by reducing the intracellular cyclic AMP concentration [3].HSL is phosphorylated at a single site by cyclic-AMPdependent protein kinase in vitro [4,5]. Peptide-mapping studies indicate that this site, which has been termed the regulatory site, is that which is phosphorylated in intact adipocytes in response to noradrenaline [6].…”

“…HSL is phosphorylated at a single site by cyclic-AMPdependent protein kinase in vitro [4,5]. Peptide-mapping studies indicate that this site, which has been termed the regulatory site, is that which is phosphorylated in intact adipocytes in response to noradrenaline [6].…”

Expression of biologically active hormone‐sensitive lipase in mammalian (COS) cells

“…HSL is also present in the steroidogenic tissues [3-61, where it functions as a cholesterol ester hydrolase and has been proposed to play an important regulatory role in the synthesis [3] and also hydrolysis [7] of steroid hormones from these tissues. The activity of HSL is under strict hormonal and neural control, a mechanism involving phosphorylation of a single serine residue (Ser-563) [6,8] by cylic AMP-dependent protein kinase [9,10]. In response to lipolytic hormones, such as noradrenaline, HSL is phosphorylated and concomitantly activated, whereas antilipolytic hormones, such as insulin, cause a net dephosphorylation and deactivation.…”