Inwardly rectifying K+ (Kir) channels allow K+ to move more easily into rather than out of the
cell. They have diverse physiological functions depending on their type and their location …

Heterotrimeric G proteins are key players in transmembrane signaling by coupling a huge
variety of receptors to channel proteins, enzymes, and other effector molecules. Multiple …

For a comprehensive understanding of human physiology—from molecules to systems—
turn to the latest edition of Medical Physiology. This updated textbook is known for its …

Ionized calcium (Ca 2÷) is the most common signal transduction element in cells ranging
from bacteria to specialized neurons. Unlike many other second-messenger mo! ecules, Ca …

Abstract GELATINASE A (type-IV collagenase; Mr 72,000) is produced by tumour stroma
cells and is believed to be crucial for their invasion and metastasis, acting by degrading …

Since the second messenger role was proposed for the products of inositol phospholipid
hydrolysis, considerable progress has been made in our understanding of the biochemical …

WD proteins are made up of highly conserved repeating units usually ending with Trp-Asp
(WD). They are found in all eukaryotes but not in prokaryotes. They regulate cellular …

▪ Abstract GTPase-activating proteins (GAPs) regulate heterotrimeric G proteins by
increasing the rates at which their α subunits hydrolyze bound GTP and thus return to the …

THE protein p21 is a dual inhibitor of cyclin-dependent kinases1á¤-3 and proliferating-cell
nuclear antigen (PCNA) 4, both of which are required for passage through the cell cycle. The …

This review is concerned with the structures and mechanisms of a superfamily of regulatory
GTP hydrolases (G proteins). G proteins include Ras and its close homologs, translation …